#include <bits/stdc++.h>

using namespace std;

int main() {
    int n, m;
    cin >> n >> m;

    string t = "LOVE";
    while (n--) {
        string s;
        cin >> s;

        for (int i = 0; i + 3 < m; i++) {
            if (s.substr(i, 4) == t) {
                cout << "YES" << endl;
                return 0;
            }
        }
    }

    cout << "NO" << endl;
    return 0;
}