#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n,a;
    cin>>n>>a;
    vector<int> x(n);
    for(int i=0;i<n;i++)cin>>x[i];
    if(a==(double)accumulate(x.begin(),x.end(),0)/n)cout<<"YES"<<endl;
    else cout<<"NO"<<endl;
    return 0;
}