#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> v(H + 2, vector<char>(W + 2, '.'));
  for (int i = 1; i < H + 1; i++) {
    for (int j = 1; j < W + 1; j++) {
      cin >> v.at(i).at(j);
    }
  }
  bool a = false;
  bool finished = false;
  for (int i = 1; i < H + 1; i++) {
    for (int j = 1; j < W + 1; j++) {
      if (v.at(i).at(j) == '.')
        continue;
      else if (v.at(i - 1).at(j) == '.' && v.at(i + 1).at(j) == '.' &&
               v.at(i).at(j - 1) == '.' && v.at(i).at(j + 1) == '.') {
        finished = true;
        break;
      }
    }
    if (finished)
      break;
    else
      a = true;
  }
  if (a)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
}
