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

int main(){
  int a,b;
  cin >> a >> b;
  char s[b];
  for(int i=0;i<a;i++){
    cin >> s;
    if(strstr(s,"LOVE")){
      cout << "YES"<<endl;
      return 0;
    }
  }
  cout << "NO" << endl;
  return 0;
}