import java.util.Scanner;

public class No700_Love {
    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        int value1 = scan.nextInt();
        int value2 = scan.nextInt();

        String[] list = new String[value1];
        for (int i = 0; i < value1; i++) {
            list[i] = scan.next();
        }
        
        for (int j = 0; j < list.length; j++) {
            if (list[j].contains("LOVE")) {
                System.out.println("YES");       
                return;
            }
        }
        System.out.println("NO");
    }
}