#include <iostream>
#include <vector>
using namespace std;
int main(){
    int n, ave, sum = 0;
    cin >> n >> ave;
    vector<int> a(n);
    for(int i = 0; i < n; i ++){
        cin >> a[i];
        sum += a[i];
    }
    if(ave * n == sum){
        cout << "YES" << endl;
    }else{
        cout << "NO" << endl;
    }
}