#include <bits/stdc++.h>
using namespace std;
#define FOR(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define FORR(i,l,n) for(int (i)=l;(i)<(int)(n);++(i))
double x[11];
void solve() {
	int n, a;
	std::cin >> n >> a;
	double sum = 0;
	FOR(i, n) {
		std::cin >> x[i];
		sum += x[i];
	}
	//平均
	sum = sum / n;

	if (sum == a) cout << "YES" << endl;
	else cout << "NO" << endl;
}
int main() {
	ios::sync_with_stdio(false);
	solve();
	return 0;
}