Maximize obj: x11+x12+x13+x14+x15+x21+x22+x23+x24+x25+x31+x32+x33 +x34+x35+x41+x42+x43+x44+x45+x51+x52+x53+x54+x55 Subject To c1: x11 + x12 + x13 + x14 + x15 <=1 c2: x21 + x22 + x23 + x24 + x25 <=1 c3: x31 + x32 + x33 + x34 + x35 <=1 c4: x41 + x42 + x43 + x44 + x45 <=1 c5: x51 + x52 + x53 + x54 + x55 <=1 c6: x11 + x21 + x31 + x41 + x51 <=1 c7: x12 + x22 + x32 + x42 + x52 <=1 c8: x13 + x23 + x33 + x43 + x53 <=1 c9: x14 + x24 + x34 + x44 + x54 <=1 c10:x15 + x25 + x35 + x45 + x55 <=1 c11:x11 + x22 + x33 + x44 + x55 <=1 c12:x12 + x23 + x34 + x45 <=1 c13:x13 + x24 + x35 <=1 c14:x21 + x32 + x43 + x54 <=1 c15:x31 + x42 + x53 <=1 c16:x13 + x22 + x31 <=1 c17:x14 + x23 + x32 + x41 <=1 c18:x15 + x24 + x33 + x42 + x51 <=1 c19:x25 + x34 + x43 + x52 <=1 c20:x35 + x44 + x53 <=1 binary x11 x12 x13 x14 x15 x21 x22 x23 x24 x25 x31 x32 x33 x34 x35 x41 x42 x43 x44 x45 x51 x52 x53 x54 x55 End