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

int main(){
  int n;
  cin>>n;
  int a[n];
  rep(i,n) cin>>a[i];
  sort(a,a+n);
  if(n%2 ==1){
    cout<<a[n/2]<<endl;
    return 0;
  }
  else{
    cout<<((double)(a[n/2])+(double)(a[n/2-1]))/2<<endl;
  }
  return 0; 
}