using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    public void Solve()
    {
        double[] NA = Console.ReadLine().Split(' ').Select(s => double.Parse(s)).ToArray();
        double[] X = Console.ReadLine().Split(' ').Select(s => double.Parse(s)).ToArray();

        double sum = 0;
        for (int i = 0; i < NA[0]; i++) { sum += X[i]; }

        Console.WriteLine(sum / NA[0] == NA[1] ? "YES" : "NO");
    }

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