#include <iostream>
#include <cstring>

using namespace std;

int main(void){
    int n, m;
    bool flag =false;
    cin >> n >> m;
    for(int i=0; i<n; i++){
        char str[51];
        cin >> str;
        for(int j=0; j<m-3; j++){
            if(str[j] == 'L'){
                if(str[j+1] == 'O' && 
                    str[j+2] == 'V' &&
                    str[j+3] == 'E')
                        cout << "Yes" << endl;
                        flag = true;
            }
        }
    }

    if(flag) cout << "No" << endl;
    return 0;
}