#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int H,W;
  cin>>H>>W;
  vector<vector<char>> S(H,vector<char>(W));
  for(int i=0;i<H;i++)for(int j=0;j<W;j++){
      cin>>S[i][j];
  }
  for(int i=0;i<H;i++)for(int j=0;j<W-3;j++)if(S[i][j] == 'L' && S[i][j+1] == 'O' && S[i][j+2] == 'V' && S[i][j+3] == 'E'){
      cout<<"YES"<<endl;
      return 0;
  }
  cout<<"NO"<<endl;
}