#include<stdio.h>
#include<algorithm>
using namespace std;
int A[2010][2010];

int main(){
	int n, m, i, j, k, ans = 0;
	scanf("%d %d", &n, &m);
	for(i=1;i<=n;i++)
		for(j=1;j<=m;j++)
			scanf("%d", &A[i][j]);
	
	for(i=1;i<=n;i++){
		for(j=1;j<=m;j++){
			for(k=0;k<=n and k<=m; k++){
				if(A[i][j]==1 and A[i][j+k]==1 and A[i+k][j]==1 and A[i+k][j+k]==1 ){
					ans = max(k, ans);
				}
			}
		}
	}
	printf("%d",(ans+1)*(ans+1));
}