6
16 17 18 19 20 1 2 3 15 21
16 17 18 19 20 1 2 4 5 7 8 9 12 13 1 2 3 15 21
16 17 18 19 20 1 2 3 15 21
16 17 18 19 20 1 2 4 5 7 8 9 12 13 1 2 3 15 21
16 17 18 19 20 1 2 4 5 7 8 9 10 1 2 3 15 21
16 17 18 19 20 1 2 4 5 6 9 12 13 1 2 3 15 14 15 21

feasible 
infeasible
feasible 
infeasible
infeasible
feasible