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

int main(){
int n;
double a;
cin >> n >>a;
double  che =0;
for(int i=0;i<n;i++){
    double z;
    cin>>z;
    che+=z;
}
che/=n;
if(a==che){
    cout <<"YES"<<endl;
}
else {
    cout <<"NO"<<endl;
}
}