#include <bits/stdc++.h>   int main(int agrc, char* argv[]) {     int N, M;     scanf( %d %d , &N, &M);     char room[625];     for (int i = 0; i < N * M; i++) scanf(  %c , room + i);     int dp[625];     for (int i = 0; i < M * M; i++) dp[i] = 0;     int best = 0;     for (int r = 0; r < N; r++) {       for (int pl = 0; pl < M; pl++)         for (int pr = pl; pr < M; pr++) {           bool free = true;           for (int i = pl; i <= pr && free; i++) free &= room[M * r + i] ==  0 ;           if (free) {             if (dp[pl * M + pr] == 0) {               dp[pl * M + pr] = 2 + 2 * (pr - pl + 1);             } else {               dp[pl * M + pr] += 2;             }           } else {             dp[pl * M + pr] = 0;           }         }       for (int i = 0; i < M * M; i++)         if (dp[i] > best) best = dp[i];     }     printf( %d n , best);     return 0;   }   