#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <fstream>
#include <set>
#include <utility>
#include <algorithm>

using namespace std;

int max(int x, int y) {
	int a;
	(x > y) ? a = x : a = y;
	return a;
}

int min(int x, int y) {
	int a;
	(x < y) ? a = x : a = y;
	return a;
}

int main() {
	int n, a;
	cin >> n >> a;
	vector<double> v(n);

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