#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int main(){
    int n;
    double ans;
    cin >> n;
    vector<int> v(n);
    for(int i=0;i<n;i++)cin >> v[i];
    sort(v.begin(),v.end());
    if(n%2==0)ans=(double)(v[n/2]+v[n/2-1])/2;
    else ans=v[n/2];
    cout << ans << endl;
}