Problem:
Largest Square

Given a matrix (H × W) which contains only 1 and 0, find the area of the largest square matrix which only contains 0s.

Input

H W
c1,1 c1,2 ... c1,W
c2,1 c2,2 ... c2,W
:
cH,1 cH,2 ... cH,W

In the first line, two integers H and W separated by a space character are given. In the following H lines, ci,j, elements of the H × W matrix, are given.

Output

Print the area (the number of 0s) of the largest square.

Constraints

1 ≤ H, W ≤ 1,400

Sample Input

4 5
0 0 1 0 0
1 0 0 0 0
0 0 0 1 0
0 0 0 1 0

Sample Output

4

Solution in Python (judge verdict: Wrong Answer)

h,w=map(int,raw_input().split())
c=[[1]*(w+1)]+[[1]+map(int,raw_input().split()) for _ in xrange(h)]
dp=[[0]*(w+1) for i in xrange(h+1)]
for i in xrange(h):
	for j in xrange(w):
		if c[i+1][j+1]==0:
			dp[i+1][j+1]=min(dp[i][j+1],dp[i+1][j],dp[i][j])+1
print(max(max(dp))**2)