* #variable= 4 #constraint= 6 #soft= 4 mincost= 2 maxcost= 5 sumcost= 14
soft: 6 ;
[2] +1 x1 >= 1;
[3] +1 x2 >= 1;
[4] +1 x3 >= 1;
[5] +1 x4 >= 1;
-1 x1 -1 x2 >= -1 ;
-1 x3 -1 x4 >= -1 ;