#include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(n); i++)
using namespace std;
typedef long long ll;

int main(){
	int n; cin>>n;
	ll a; cin>>a;
	vector<ll> v(n);
	rep(i,n) cin>>v[i];
	ll ans=0;
	rep(i,n) ans+=v[i];
	if(a==(double)ans/n) cout << "YES" << endl;
	else cout << "NO" << endl;	
}