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(' ') ;
            string[] input2 = Console.ReadLine().Split(' ') ;
            double maians = int.Parse(input[1]);
            double trueans = 0;
            for(int i=0;i<input2.Length;i++)
            {
                trueans = trueans + int.Parse(input2[i]);
            }
            trueans = trueans / int.Parse(input[0]);
            if(maians==trueans)
            {
                Console.WriteLine("YES");
            }
            else
            {
                Console.WriteLine("NO");
            }
        }

    }
}