#include <iostream>
using namespace std;

int main()
{
	int n;
	double a;
	double b=0;
	int x;
	cin>>n>>a;
	for(int i=0;i<n;i++){
		cin>>x;
		b+=x;
	}
	if((b/n==a))cout<<"YES"<<endl;
	else cout<<"NO"<<endl;

	return 0;

}