#include <bits/stdc++.h>

using namespace std;

int main() {
  int n, m;
  cin >> n >> m;
  bool love = false;
  for (int i = 0; i < n; ++i) {
    string s;
    cin >> s;
    if (m < 4) continue;
    for (int j = 0; j < m - 3; ++j) {
      string sub = s.substr(j, 4);
      if (sub == "LOVE") love = true;
    }
  }
  cout << (love? "YES": "NO") << '\n';	      
  return 0;
}