//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  ll N, A; cin >> N >> A;
  ll ans = N*A;
  
  for(int i = 0; i < N; i++){
    int X; cin >> X;
    
    ans -= X;
  }
  
  ans == 0 ? printl("YES") : printl("NO");
  
  return 0;
}