check 1 2 1
check 2 5 1
check 3 5 0
check 4 0 0
check 5 0 5
check 4 5 8
check 3 5 8
check 3 6 1
check 4 6 9
check 5 3 9
check 2 6 1
check 3 6 9
check 4 3 9
7