import java.util.Scanner;
public class main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		for (int i=0; i<n; i++) {
			String s = sc.next();
			if (s.indexOf("LOVE") > 0) {
				System.out.println("YES");
				return;
			}
		}
		System.out.println("NO");
	}
}