#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

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

    return 0;
}