#include<cstdio>
#include<algorithm>

using namespace std;
int mat[105][105];
int main()
{
  int n, m, i, j, max = 0;
  char c;
  scanf("%d%d\n", &n, &m);
  for(i = 1; i <= n; ++ i)
  {
    for(j = 1; j <= m; ++ j)
    {
      scanf("%c", &c);
      if(c != '&')
      {
        mat[i][j] = mat[i-1][j];
        if(mat[i][j] < mat[i][j-1])
          mat[i][j] = mat[i][j - 1];
        ++ mat[i][j];
        if(max < mat[i][j])
          max = mat[i][j];
      }
    }
    scanf("\n");
  }
  printf("%d\n", max);
  return 0;
}