#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll=vector<long long>;
template<typename T>
T get(){T r;cin>>r;return r;}

int main() {
    ll n,a;
    cin>>n>>a;
    vll x;
    double sum=0;
    for(ll i=0;i!=n;i++) x.push_back(get<ll>());
    for(ll i=0;i!=n;i++) sum+=x[i];
    if((double)a==sum/n){
        cout<<"YES"<<endl;
    }
    else{
        cout<<"NO"<<endl;
    }

    system("pause");
}