Trace number 426653

Some explanations

A solver is run under the control of another program named runsolver. runsolver is in charge of imposing the CPU time limit and the memory limit to the solver. It also monitors some information about the process. The trace of the execution of a solver is divided into four (or five) parts:
  1. SOLVER DATA
    This is the output of the solver (stdout and stderr).
    Note that some very long lines in this section may be truncated by your web browser ! In such a case, you may want to use the "Download as text" link to get the trace as a text file.

    When the --timestamp option is passed to the runsolver program, each line output by the solver is prepended with a timestamp which indicates at what time the line was output by the solver. Times are relative to the start of the program, given in seconds, and are wall clock time (not CPU time).

    As some 'v lines' may be very long (sometimes several megabytes), the 'v line' output by your solver may be split on several lines to help limit the size of the trace recorded in the database. In any case, the exact output of your solver is preserved in a trace file.
  2. VERIFIER DATA
    The output of the solver is piped to a verifier program which will search a value line "v " and, if found, will check that the given interpretation satisfies all constraints.
  3. CONVERSION SCRIPT DATA (Optionnal)
    When a conversion script is used, this section shows the messages that were output by the conversion script.
  4. WATCHER DATA
    This is the informations gathered by the runsolver program. It first prints the different limits. There's a first limit on CPU time set to X seconds (see the parameters in the trace). After this time has ellapsed, runsolver sends a SIGTERM and 2 seconds later a SIGKILL to the solver. For safety, there's also another limit set to X+30 seconds which will send a SIGXPU to the solver. The last limit is on the virtual memory used by the process (see the parameters in the trace).
    Every ten seconds, the runsolver process fetches the content of /proc/loadavg, /proc/pid/stat and /proc/pid/statm (see man proc) and prints it as raw data. This is only recorded in case we need to investigate the behaviour of a solver. The memory used by the solver (vsize) is also given every ten seconds.
    When the solver exits, runsolver prints some informations such as status and time. CPU usage is the ratio CPU Time/Real Time.
  5. LAUNCHER DATA
    These informations are related to the script which will launch the solver. The most important informations are the command line given to the solver, the md5sum of the different files and the dump of the /proc/cpuinfo and /proc/meminfo which provides some useful information on the computer.

Solver answer on this benchmark

Solver NameAnswerCPU timeWall clock time
DEWSATZ 1A 2007-02-08SAT 185.064 185.131

General information on the benchmark

Namerandom/OnTreshold/7SAT/v50/
unif-k7-r89-v50-c4450-S1830776056-07.SAT.shuffled.cnf
MD5SUM68cb6fbbdabed63f11100cea94c92cef
Bench CategoryRANDOM (random instances)
Best result obtained on this benchmarkSAT
Best CPU time to get the best result obtained on this benchmark0.12698
Satisfiable
(Un)Satisfiability was proved
Number of variables50
Number of clauses4450
Sum of the clauses size31150
Maximum clause length7
Minimum clause length7
Number of clauses of size 10
Number of clauses of size 20
Number of clauses of size 30
Number of clauses of size 40
Number of clauses of size 50
Number of clauses of size over 54450

Solver Data (download as text)

185.02/185.12	c   
185.02/185.12	c =====================================================================================================
185.02/185.12	c Copyright (c) 2004 National ICT Australia Limited (NICTA) and applicable third parties.
185.02/185.12	c For details, see the Australian Public Licence B (OZPLB) V1-1, under which this software is licensed.
185.02/185.12	c The OZPLB text is embedded in the source code for this software.
185.02/185.12	c =====================================================================================================
185.02/185.12	c   
185.02/185.12	c solution of Dew_Satz_1a.c 
185.02/185.12	s SATISFIABLE
185.02/185.12	v -1 -2 3 -4 -5 6 7 8 -9 10 -11 12 13 14 -15 16 17 -18 19 -20 -21 -22 -23 24 25 26 -27 28 29 -30 -31 32 33 34 35 36 -37 38 39 40 -41 42 43 -44 -45 46 47 48 49 50 0 
185.02/185.12	c Dew_Satz_1a /tmp/evaluation/426653-1177827804/instance-426653-1177827804.cnf 1 185.070  3.080 42371 42371 0 42371 42383 3918395 423702 795941 208584 4450 4450 50 0 0 50

Verifier Data (download as text)

OK

Watcher Data (download as text)

runsolver version 3.2.3 (c) roussel@cril.univ-artois.fr

command line: runsolver --timestamp -w ROOT/results/node58/watcher-426653-1177827804 -o ROOT/results/node58/solver-426653-1177827804 -C 5000 -W 7500 -M 1800 --output-limit 1,15 /tmp/evaluation/426653-1177827804/dewSatz_1a /tmp/evaluation/426653-1177827804/instance-426653-1177827804.cnf 

Enforcing CPUTime limit (soft limit, will send SIGTERM then SIGKILL): 5000 seconds
Enforcing CPUTime limit (hard limit, will send SIGXCPU): 5030 seconds
Enforcing wall clock limit (soft limit, will send SIGTERM then SIGKILL): 7500 seconds
Enforcing VSIZE limit (soft limit, will send SIGTERM then SIGKILL): 1843200 KiB
Enforcing VSIZE limit (hard limit, stack expansion will fail with SIGSEGV, brk() and mmap() will return ENOMEM): 1894400 KiB
Solver output will be limited to a maximum of 15728640 bytes. The first 1048576 bytes and the last 14680064 bytes will be preserved
Current StackSize limit: 10240 KiB


[startup+0 s]
/proc/loadavg: 0.99 0.97 0.96 3/64 17778
/proc/meminfo: memFree=1591240/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=674392 CPUtime=0
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 70 0 0 0 0 0 0 0 19 0 1 0 230690065 690577408 56 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134575619 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168598 56 41 100 0 168495 0

[startup+0.067196 s]
/proc/loadavg: 0.99 0.97 0.96 3/64 17778
/proc/meminfo: memFree=1591240/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=674796 CPUtime=0.06
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 9962 0 0 0 5 1 0 0 19 0 1 0 230690065 690991104 180 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134517872 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168699 180 42 100 0 168596 0
Current children cumulated CPU time (s) 0.06
Current children cumulated vsize (KiB) 674796

[startup+0.1012 s]
/proc/loadavg: 0.99 0.97 0.96 3/64 17778
/proc/meminfo: memFree=1591240/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=674796 CPUtime=0.09
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 9965 0 0 0 8 1 0 0 19 0 1 0 230690065 690991104 183 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134520892 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168699 183 42 100 0 168596 0
Current children cumulated CPU time (s) 0.09
Current children cumulated vsize (KiB) 674796

[startup+0.301232 s]
/proc/loadavg: 0.99 0.97 0.96 3/64 17778
/proc/meminfo: memFree=1591240/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=674796 CPUtime=0.29
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 9975 0 0 0 28 1 0 0 20 0 1 0 230690065 690991104 193 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134515634 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168699 193 42 100 0 168596 0
Current children cumulated CPU time (s) 0.29
Current children cumulated vsize (KiB) 674796

[startup+0.701299 s]
/proc/loadavg: 0.99 0.97 0.96 3/64 17778
/proc/meminfo: memFree=1591240/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=674936 CPUtime=0.69
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 9986 0 0 0 68 1 0 0 24 0 1 0 230690065 691134464 204 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134515719 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168734 204 42 100 0 168631 0
Current children cumulated CPU time (s) 0.69
Current children cumulated vsize (KiB) 674936

[startup+1.50143 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1590400/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=674936 CPUtime=1.49
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10000 0 0 0 148 1 0 0 25 0 1 0 230690065 691134464 218 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134515644 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168734 218 42 100 0 168631 0
Current children cumulated CPU time (s) 1.49
Current children cumulated vsize (KiB) 674936

[startup+3.1027 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1590208/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=3.09
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10079 0 0 0 308 1 0 0 25 0 1 0 230690065 691277824 297 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134531983 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 297 45 100 0 168666 0
Current children cumulated CPU time (s) 3.09
Current children cumulated vsize (KiB) 675076

[startup+6.30124 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589760/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=6.29
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10092 0 0 0 628 1 0 0 25 0 1 0 230690065 691277824 310 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134525319 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 310 45 100 0 168666 0
Current children cumulated CPU time (s) 6.29
Current children cumulated vsize (KiB) 675076

[startup+12.7013 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589632/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=12.69
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10094 0 0 0 1268 1 0 0 25 0 1 0 230690065 691277824 312 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134534929 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 312 45 100 0 168666 0
Current children cumulated CPU time (s) 12.69
Current children cumulated vsize (KiB) 675076

[startup+25.5015 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589632/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=25.48
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10094 0 0 0 2547 1 0 0 25 0 1 0 230690065 691277824 312 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134535078 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 312 45 100 0 168666 0
Current children cumulated CPU time (s) 25.48
Current children cumulated vsize (KiB) 675076

[startup+51.1017 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589632/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=51.07
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10096 0 0 0 5106 1 0 0 25 0 1 0 230690065 691277824 314 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134535690 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 314 45 100 0 168666 0
Current children cumulated CPU time (s) 51.07
Current children cumulated vsize (KiB) 675076

[startup+102.305 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=102.26
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10096 0 0 0 10225 1 0 0 25 0 1 0 230690065 691277824 314 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134534920 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 314 45 100 0 168666 0
Current children cumulated CPU time (s) 102.26
Current children cumulated vsize (KiB) 675076

[startup+162.301 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589632/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=162.23
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10096 0 0 0 16222 1 0 0 25 0 1 0 230690065 691277824 314 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134535078 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 314 45 100 0 168666 0
Current children cumulated CPU time (s) 162.23
Current children cumulated vsize (KiB) 675076

Solver just ended. Dumping a history of the last processes samples

[startup+166.302 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589632/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=166.23
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10096 0 0 0 16622 1 0 0 25 0 1 0 230690065 691277824 314 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134535191 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 314 45 100 0 168666 0
Current children cumulated CPU time (s) 166.23
Current children cumulated vsize (KiB) 675076

[startup+172.705 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=172.63
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10096 0 0 0 17262 1 0 0 25 0 1 0 230690065 691277824 314 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134523581 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 314 45 100 0 168666 0
Current children cumulated CPU time (s) 172.63
Current children cumulated vsize (KiB) 675076

[startup+179.101 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=179.03
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10096 0 0 0 17902 1 0 0 25 0 1 0 230690065 691277824 314 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134528245 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 314 45 100 0 168666 0
Current children cumulated CPU time (s) 179.03
Current children cumulated vsize (KiB) 675076

[startup+182.302 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=182.23
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10097 0 0 0 18222 1 0 0 25 0 1 0 230690065 691277824 315 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134513504 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 315 45 100 0 168666 0
Current children cumulated CPU time (s) 182.23
Current children cumulated vsize (KiB) 675076

[startup+183.902 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=183.83
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10097 0 0 0 18382 1 0 0 25 0 1 0 230690065 691277824 315 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134535078 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 315 45 100 0 168666 0
Current children cumulated CPU time (s) 183.83
Current children cumulated vsize (KiB) 675076

[startup+184.701 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=184.63
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10097 0 0 0 18462 1 0 0 25 0 1 0 230690065 691277824 315 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134536157 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 315 45 100 0 168666 0
Current children cumulated CPU time (s) 184.63
Current children cumulated vsize (KiB) 675076

[startup+185.101 s]
/proc/loadavg: 0.99 0.97 0.96 2/65 17779
/proc/meminfo: memFree=1589568/2055920 swapFree=4184532/4192956
[pid=17778] ppid=17776 vsize=675076 CPUtime=185.02
/proc/17778/stat : 17778 (dewSatz_1a) R 17776 17778 17106 0 -1 4194304 10097 0 0 0 18501 1 0 0 25 0 1 0 230690065 691277824 315 18446744073709551615 134512640 134924432 4294956656 18446744073709551615 134536159 0 0 4096 0 0 0 0 17 1 0 0
/proc/17778/statm: 168769 315 45 100 0 168666 0
Current children cumulated CPU time (s) 185.02
Current children cumulated vsize (KiB) 675076

Child status: 10
Real time (s): 185.131
CPU time (s): 185.064
CPU user time (s): 185.048
CPU system time (s): 0.015997
CPU usage (%): 99.9636
Max. virtual memory (cumulated for all children) (KiB): 675076

getrusage(RUSAGE_CHILDREN,...) data:
user time used= 185.048
system time used= 0.015997
maximum resident set size= 0
integral shared memory size= 0
integral unshared data size= 0
integral unshared stack size= 0
page reclaims= 10111
page faults= 0
swaps= 0
block input operations= 0
block output operations= 0
messages sent= 0
messages received= 0
signals received= 0
voluntary context switches= 6
involuntary context switches= 349

runsolver used 0.12998 second user time and 0.381941 second system time

The end

Launcher Data (download as text)

Begin job on node58 on Sun Apr 29 06:23:24 UTC 2007

IDJOB= 426653
IDBENCH= 19895
IDSOLVER= 195
FILE ID= node58/426653-1177827804

PBS_JOBID= 4718274

Free space on /tmp= 66563 MiB

SOLVER NAME= DEWSATZ 1A 2007-02-08
BENCH NAME= HOME/pub/bench/SAT07/random/OnTreshold/7SAT/v50/unif-k7-r89-v50-c4450-S1830776056-07.SAT.shuffled.cnf
COMMAND LINE= /tmp/evaluation/426653-1177827804/dewSatz_1a /tmp/evaluation/426653-1177827804/instance-426653-1177827804.cnf            
RUNSOLVER COMMAND LINE= runsolver  --timestamp  -w ROOT/results/node58/watcher-426653-1177827804 -o ROOT/results/node58/solver-426653-1177827804 -C 5000 -W 7500 -M 1800 --output-limit 1,15  /tmp/evaluation/426653-1177827804/dewSatz_1a /tmp/evaluation/426653-1177827804/instance-426653-1177827804.cnf            

META MD5SUM SOLVER= d41d8cd98f00b204e9800998ecf8427e
MD5SUM BENCH=  68cb6fbbdabed63f11100cea94c92cef

RANDOM SEED= 969769947

TIME LIMIT= 5000 seconds
MEMORY LIMIT= 1800 MiB

Linux node58.alineos.net 2.6.9-22.EL.rootsmp #1 SMP Mon Oct 3 08:59:52 CEST 2005 x86_64 x86_64 x86_64 GNU/Linux

/proc/cpuinfo:
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 4
model name	:                   Intel(R) Xeon(TM) CPU 3.00GHz
stepping	: 3
cpu MHz		: 3000.265
cache size	: 2048 KB
fpu		: yes
fpu_exception	: yes
cpuid level	: 5
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm pni monitor ds_cpl cid cx16 xtpr
bogomips	: 5914.62
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 15
model		: 4
model name	:                   Intel(R) Xeon(TM) CPU 3.00GHz
stepping	: 3
cpu MHz		: 3000.265
cache size	: 2048 KB
fpu		: yes
fpu_exception	: yes
cpuid level	: 5
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm pni monitor ds_cpl cid cx16 xtpr
bogomips	: 5586.94
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:


/proc/meminfo:
MemTotal:      2055920 kB
MemFree:       1591648 kB
Buffers:         44676 kB
Cached:         339776 kB
SwapCached:       2604 kB
Active:         258516 kB
Inactive:       135748 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:      2055920 kB
LowFree:       1591648 kB
SwapTotal:     4192956 kB
SwapFree:      4184532 kB
Dirty:            1488 kB
Writeback:           0 kB
Mapped:          16120 kB
Slab:            56140 kB
Committed_AS:  1194908 kB
PageTables:       1380 kB
VmallocTotal: 536870911 kB
VmallocUsed:    264952 kB
VmallocChunk: 536605679 kB
HugePages_Total:     0
HugePages_Free:      0
Hugepagesize:     2048 kB

Free space on /tmp at the end= 66563 MiB

End job on node58 on Sun Apr 29 06:26:29 UTC 2007