//#include <atcoder/all>
#include <bits/stdc++.h>
#include <cmath>
using namespace std;
//using namespace atcoder;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
using Graph = vector<vector<ll>>;

int main() {
	ll N,M;
	cin>>N>>M;
	rep(n,N){
		string S;
		cin>>S;
		rep(m,M-3){
			if(S.substr(m,4)=="LOVE"){
				cout<<"YES"<<endl;
			return 0;}
		}
	}
	cout<<"NO"<<endl;
	return 0;

}