#include <bits/stdc++.h>
using namespace std;

int main(){
  int n;
  double a;
  cin>>n>>a;
  double A[n];
  double sum=0;
  for(int i=0;i<n;i++){
    cin>>A[i];
    sum+=A[i];
  }
  if((double)sum/n==a){
    cout<<"YES"<<endl;
  }
  else{
    cout<<"NO"<<endl;
  }
    
 
  return 0;
}