#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
  int n;
  cin>>n;
  double a[n];
  for(int i=0;i<n;i++) cin>>a[i];
  sort(a,a+n);
  if(n%2) cout<<a[n/2]<<endl;
  else cout<<(a[n/2-1]+a[n/2])/2.0<<endl;
  return 0;
}