7 7
1 2 2 2 2 2 1
1 -1 2 -1 2 -1 1
3 -2 -2 6 -2 -2 3
4 -1 -4 -1 8 -1 -2
3 1 -2 -3 -2 1 3
12 13 4 -3 -8 -11 -6
12 -11 4 -3 -8 13 -6
