#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string
#include <cstdlib>		//abs(int)
#include <utility>		//swap, pair
#include <deque>		//deque
#include <climits>		//INT_MAX
#include <bitset>		//bitset
#include <cmath>		//sqrt, ceil. M_PI, pow, sin
#include <ios>			//fixed
#include <iomanip>		//setprecision

using namespace std;

int main() {

	int n, a;
	cin >> n >> a;

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

	double ave = sum / n;
	double ans = round(ave * 100) / 100;

	if (a == ans) {
		cout << "YES" << endl;
	}
	else {
		cout << "NO" << endl;
	}

	return 0;

}