#include<bits/stdc++.h>
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());
    
    if(n % 2==1) cout << a[n/2] << endl;
    else{
        if((a[n/2]+a[n/2-1])%2==0) cout << (a[n/2]+a[n/2-1])/2 << endl;
        else{
            double ans=(a[n/2]+a[n/2-1])/2.0;
            cout << ans << endl;
        }
    }
}