#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
#include <math.h>
#include <iomanip>
using namespace std;
#define Would
#define you
const int INF = 999999999;
const int MOD = 1e9 + 7;

int main() {
	long long a, b, k[15], sum = 0;
	cin >> a >> b;
	for (int i = 0; i < a; ++i) {
		cin >> k[i];
		sum += k[i];
	}
	if ((double)sum / a == b) { cout << "YES" << endl; }
	else { cout << "NO" << endl; }
}