#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
typedef long long ll;

int main(){
  double n, a;
  cin >> n >> a;
  int sum = 0;
  FOR(i,0,n){
    double in;
    cin >> in;
    sum += in;
  }
  if(sum/n == a){
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}