package algo;

import java.util.ArrayList;
import java.util.Scanner;

import java.util.*;

public class sample7 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		String a = "NO";
		for(int i=0; i < n; i++) {
			String s = sc.next();
			String s2 = "LOVE";
			if(s.indexOf("LOVE") != -1) {
				a = "YES";
				System.out.println(a);
				return;
			}
			else {
			}
		}
		System.out.println(a);
	}
}