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

int main(){
  int n, m; cin >> n >> m;
  string LOVE = "LOVE";
  for (int i = 0; i < n; i++) {
    string s; cin >> s;
    for (int j = 0; j < m; j++) {
      for (int k = 0; k < 4; k++) {
        if (j+k >= m) break;
        if (s[j+k] != LOVE[k]) break;
        if (k == 3) {
          cout << "YES" << endl;
          return 0;
        }
      }
    }
  }
  cout << "NO" << endl;
  return 0;
}