#include <bits/stdc++.h>
using namespace std;
int main() {
  int dx[4] = {1, 0, -1, 0};
  int dy[4] = {0, 1, 0, -1};
  int h, w;
  cin >> h >> w;
  string d[50];
  for (int i = 0; i < h; i++) cin >> d[i];
  int num = 0;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (d[i][j] == '.') continue;
      for (int k = 0; k < 4; k++) {
        int y = i + dy[k];
        int x = j + dx[k];
        if (y < 0 | y >= h) continue;
        if (x < 0 | x >= w) continue;
        if (d[y][x]) num++;
      }
    }
  }
  if (num == 0)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
}
