#include <bits/stdc++.h>

#define REP(i, n) for (int i = 0; i < (n); i++)
#define FOR(i, init, n) for (int i = init; i < (n); i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define Cout(obj) cout << obj << endl
#define Size(obj) (obj).size()
#define fcout cout << fixed << setprecision(10)
#define fi first
#define se second

using namespace std;
using ll = long long int;
using P = pair<int, int>;
using T = tuple<int, int, int>;
using edge = struct
{
    int to, cost;
};

const int MOD = 1e9 + 7;
const int iINF = 1e9;
const long long int llINF = 1e18;
const double PI = acos(-1.0);

const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N, M;
    cin >> N >> M;

    vector<string> s(N);

    REP(i, N)
    {
        cin >> s[i];
    }

    REP(i, N)
    {
        REP(j, M)
        {

            if(!(j + 3 < M))
                continue;
            
            if (s[i][j] == 'L' && s[i][j + 1] == 'O' && s[i][j + 2] == 'V' && s[i][j + 3] == 'E')
            {
                Cout("YES");
                
                return 0;
            }
        }
    }

    Cout("NO");

    return 0;
}