#include <iostream> #include <algorithm> #include <cstdio> #include <string> #define ll long long using namespace std; int main(){ ll n,sum=0,a,x; cin>>n>>a; for(int i=0;i<n;++i){ cin>>x; sum+=x; } if(a*n==sum) cout<<"YES"<<endl; else cout<<"NO"<<endl; return 0; }