#include<iostream>
#include<stdio.h>
#include<vector>
#include<algorithm>

using namespace std;

int main(){
    int n;
    cin>> n;
    vector<int> a(n);
    for(int i=0; i<n; i++){
        cin>> a[i];
    }

    sort(a.begin(), a.end());

    double ans;
    if(n%2 == 1){
        cout<< a[n/2]<< endl;
    }else{
        ans = (a[n/2] + a[(n/2-1)])/2.0;
        cout<< ans<< endl;
    }

    return 0;
}