4
1 1 1
-1 1 1
-1 -1 1
1 -1 1
7
= 0 0 3 3 2
= -3 -3 0 0 2
? 0 0 3 3
? -3 -3 3 3
= -1 -1 1 1 0
? 0 0 0 0
? -1000 -1000 1000 1000