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();
        List<String> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.next());
        }
        solve(n,list);
    }
    
    static void solve(int n, List<String> list) {
        final String TARGET = "LOVE";
        if(discover(list,TARGET)) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
    
    static boolean discover(List<String> list, String target) {
        for(String tmp : list) {
            if(tmp.contains(target)) {
                return true;
            }
        }
        return false;
    }
}