* #variable= 5 #constraint= 4
*
* comments
*
* 
min: 1 x2 -1 x3 ;
1 x1 +4 x2 -2 x5 >=2;
-1 x1 +4 x2 -2 x5 >= 3;
* a big number
12345678901234567890 x4 +4 x3 >= 10;
2 x2 +3 x4 +2 x1 +3 x5 = 5 ;
* the end