min: -3 x1 - 4 x2+ -5 x3+ 4 x4+ 4 x5 + 2 x6; x1 -x6 < 0; x1 - x5 < 0; x2 - x4 < 0; x2 - x5 < 0; x3 - x4 < 0; x1+x2+x3 < 2; x1 < 1; x2 < 1; x3 < 1; x4 < 1; x5 < 1; x6 < 1; int x1, x2, x3;