#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;
        //cout << str << endl;
        for(int j=0; j<m-2; j++){
            if(str[j] == 'L'){
                if(str[j+1] == 'O' && str[j+2] == 'V' && str[j+3] == 'E'){
                    cout << "Yes" << endl;
                    flag = true;
                    break;
                }
            }
        }
        if(flag == true) break;
    }

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