#include<string>
#include<iostream>
#include<algorithm>
#include<set>
#include<unordered_set>
#include<math.h>
#include<vector>
#include<sstream>
#include<queue>
#include<functional>
#include<bitset>
#include<cstdio>
#include<iomanip>
#include <cstring>
#include <climits>
using namespace std;
#define rep(i,n) for(int (i)=0;(i) < (n); (i)++)
#define FIND(v, k) find((v).begin(), (v).end(), k)
#define MAX 101
#define MAX_V 15
#define mset(a,x) memset(a,x,sizeof(a))
int main() {
	long long res = 0; 
	double a;
	int n, t;
	cin >> n >> a;
	rep(i, n) {
		cin >> t;
		res += t;
	}
	cout << (res == a * n? "YES" : "NO") << endl;
	return 0;
}