#include <iostream>
using namespace std;
int main(void){
  int N, M;
  cin >> N >> M;
  string str;
  for(int i=0;i<N;i++){
    cin >> str;
    if(0 <= (int)str.find("LOVE")){
      cout << "YES";
      return 0;
    }
  }
  cout << "NO";
  return 0;
  
}