using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] input = Console.ReadLine().Split(' ');
            int n = int.Parse(input[0]);
            int m = int.Parse(input[1]);
            string str = "";
            bool flg = false;
            for (int i = 0; i < n; i++)
            {
                str = Console.ReadLine();
                for(int j=0;j<str.Length-3;j++)
                {
                    string temp = str.Substring(j, 4);
                    if(temp=="LOVE")
                    {
                        Console.WriteLine("YES");
                        flg = true;
                        break;
                    }
                }
                if(flg==true)
                {
                    break;
                }
            }    
            if(flg==false)
            {
                Console.WriteLine("NO");
            }
        }
    }
}