using System;
using System.Text.RegularExpressions;
using System.Linq;

class Program
{
    public void Solve()
    {
        int[] nm = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
        bool isLOVE = false;
        for (int i = 1; i <= nm[0]; i++)
        {
            var s = Console.ReadLine();
            if (isLOVE) { continue; }
            isLOVE = 0 <= s.IndexOf("LOVE");
        }
        Console.WriteLine(isLOVE ? "YES" : "NO");
    }

    static void Main()
    {
        var solver = new Program();
        solver.Solve();
    }
}