#include <bits/stdc++.h>
using namespace std;
const string LOVE = "LOVE";

int main() {
    int n, m;
    string s;
    bool ok = false;
    cin >> n >> m;
    while (n--) {
        cin >> s;
        ok |= (s.find(LOVE) != string::npos);
    }
    
    cout << (ok ? "YES" : "NO") << endl;
    return 0;
}