#include <iostream>
#include <string>
#include <algorithm>
#include <cctype>
using namespace std;

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