#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#define all(x) x.begin(),x.end()
#define pb push_back
#define ll long long 
#define P pair<int,int>
#define LP pair<ll,ll>
using namespace std;
int main() {
	double n,a;
	double sum = 0;
	cin >>n>>a;
	vector<double> x(n);
	for (int i = 0; i < n; i++) {
		cin >> x[i];
		sum += x[i];
	}
	if (sum/n == a) cout << "YES" << endl;
	else cout << "NO" << endl;
	
	return 0;
}