using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;

class Program
{
    static void Main()
    {
        var nm = ReadLine().Split().Select(int.Parse).ToArray();
        for (int i = 0; i < nm[0]; i++)
        {
            var line = ReadLine();
            for (int j = 0; j < nm[1] - 4; j++)
            {
                if (line.Substring(j, 4) == "LOVE")
                {
                    WriteLine("YES");
                    return;
                }
            }
        }
        WriteLine("NO");
    }
}