#include <bits/stdc++.h>
using namespace std;

int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    for (int j = 0; j < m - 3; j++) {
      if (s.substr(j, 4) == "LOVE") {
        cout << "YES" << endl;
        return 0;
      }
    }
  }
  cout << "NO" << endl;
  return 0;
}