/* -*- coding: utf-8 -*-
 *
 * 700.cc: No.700 LOVE - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_W = 64;

/* typedef */

/* global variables */

char s[MAX_W];

/* subroutines */

/* main */

int main() {
  int h, w;
  scanf("%d%d", &h, &w);

  for (int y = 0; y < h; y++) {
    scanf("%s", s);
    for (int x = 0; x + 4 <= w; x++)
      if (s[x] == 'L' && s[x + 1] == 'O' &&
	  s[x + 2] == 'V' && s[x + 3] == 'E') {
	puts("YES");
	return 0;
      }
  }

  puts("NO");
  return 0;
}