using System;
class Program
{
    static void Main(string[] args)
    {
        string[] inputTop = Console.ReadLine()!.Split(' ');
        string[] inputBottom = Console.ReadLine()!.Split(' ');
        double total = double.Parse(inputTop[0]);
        double result = double.Parse(inputTop[1]);
        double sum = 0;

        for (int i = 0; i < inputBottom.Length; i++)
        {
            sum += int.Parse(inputBottom[i]);
        }

        double ans = sum / total;

        if (ans == result)
        {
            Console.WriteLine("YES");
        }
        else
        {
            Console.WriteLine("NO");
        }
    }
}