using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = int.Parse(line[0]);
        var m = int.Parse(line[1]);
        if (m < 4) { Console.WriteLine("NO"); goto end; }
        for (int i = 0; i < n; i++)
        {
            var s = Console.ReadLine().Trim();
            if (s.IndexOf("LOVE") != -1) { Console.WriteLine("YES"); goto end; }
        }
        Console.WriteLine("NO");
        end:;
    }
}