import java.util.*;

class Main{
	public static void main(String[] A){
		Scanner s=new Scanner(System.in);
		int n=s.nextInt();
		s.nextInt();
		for(int i=0;i<n;++i) {
			if(s.next().contains("LOVE")) {
				System.out.println("YES");
				return;
			}
		}
		System.out.println("NO");
	}
}