#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <algorithm>
#include <string>
#include <sstream>
#include <complex>
#include <vector>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <set>
using namespace std;
typedef long long unsigned int ll;

#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))

int main() {
    int n,a;
    ll all=0;
    cin >> n>>a;
    int x;
    for (int i=0;i<n;i++){
        cin >>x;
        all+=x;
    }
    if(1.0*all/n==a)
        cout<<"YES"<<"\n";
    else
        cout<<"NO"<<"\n";
    
    return 0;
    
}