#include <bits/stdc++.h>

using namespace std;

#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define rep(i, j) FOR(i, 0, j)
#define repr(i, j) for(int i = j; i >= 0; --i)
#define INF (1 << 30)
#define MOD 1e9 + 7

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;

int main() {
	double n;
	double a, x[10];
	scanf("%lf %lf", &n ,&a);
	double sum = 0;
	rep(i, n) {
		scanf("%lf", &x[i]);
		sum += x[i];
	}
	printf("%s\n", (sum / n == a) ? "YES" : "NO");
	return 0;
}