#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int n;
  cin>>n;
  vector<double> vec(n);
  rep(i,n){
  	cin>>vec.at(i);
  }
  sort(vec.begin(),vec.end());
  if(n%2==1){
  	cout<<vec.at(n/2)<<endl;
  }
  else{
  	double ans=(vec.at(n/2-1)+vec.at(n/2))/2;
  	cout<<ans<<endl;
  }
  
}