#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;

ll n,a,x,sum;

int main () {
    cin.tie(0); ios::sync_with_stdio(false); 

    cin >> n >> a;
    rep(i,n) cin >> x, sum+=x;
    cout << (sum==a*n ? "YES" : "NO") << '\n'; 
}