#include<iostream>
#include<string>
#include<algorithm>
#include<cmath>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include<cstring>
#include<map>
using namespace std;
 
int main(){

  long long int n, a, x[10], total=0;
  cin >> n >> a;
  for(int i=0; i<n; i++){
    cin >> x[i];
    total+=x[i];
  }

  double ave=(double)total;
  ave/=(double)n;
  if((double)ave==(double)a){
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }

  return 0;
}