#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    int n, m;
    string s, l = "LOVE";
    cin >> n >> m;
    for (int i = 0; i < n; i++){
        cin >> s;
        if (s.find(l) != string::npos){
            cout << "YES" << endl;
            return 0;
        }
    }
    cout << "NO" << endl;
}