#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <map>
#include <iomanip>
#include <math.h> 
#include <stack>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <tuple>
#include <cctype>
#include <ctype.h>
#include <set>
#include <sstream>

using namespace std;


int main() {
	int i, j, k;
	double n, a;
	vector<double>x;

	cin >> n >> a;

	double sum = 0;

	for (i = 0; i < (int)n; i++) {
		double num;
		cin >> num;
		sum += num;
	}

	if (sum / n == a) {
		cout << "YES" << endl;
	}
	else {
		cout << "NO" << endl;
	}






	getchar();
	getchar();
	return 0;
}