import java.util.*;
public class Main{
    public static void main (String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        boolean isLove =false;
        for(int i = 0; i<n ;i++){
            String s = sc.next();
            if(s.contains("LOVE")){
                isLove = true;
            }
        }
        if(isLove){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
        
    }
}