#include <iostream>
using namespace std;

int n, a;
double x;

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