#define _USE_MATH_DEFINES

#include <iostream>	//cin, cout
#include <vector>	//vector
#include <algorithm> //sort,min,max,count
#include <string>	//string,getline
#include <ios>		//fixed
#include <iomanip>	//setprecision
#include <utility> //swap
#include <cstdlib>	//abs(int)
#include <cmath>	//sqrt
#include <sstream>	//stringstream,getline
#include <cmath>	//ceil,M_PI
#include <numeric>	//gcd

using namespace std;

int main() {

	int n;
	double a;
	cin >> n >> a;

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

	double ave = sum / n;
	if (a == ave) {
		cout << "YES" << endl;
	}
	else {
		cout << "NO" << endl;
	}
	
	return 0;

}