using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
class Program
{
    static void Main()
    {
        double[] Q = Array.ConvertAll(Console.ReadLine().Split(' '), r => double.Parse(r));
        double[] R = Array.ConvertAll(Console.ReadLine().Split(' '), r => double.Parse(r));
        if(R.Sum() / Q[0] == Q[1])
        {
            Console.WriteLine("YES");
        }
        else
        {
            Console.WriteLine("NO");
        }
    }
}