#include <iostream>
#include <algorithm>
using namespace std;
int main(void){
    int n;cin>>n;
    int lst[n];
    
    for(int i=0;i<n;i++)cin>>lst[i];
    sort(lst,lst+n);
    
    if(n%2==0){
        double ans = (lst[n/2-1]+lst[n/2]+0.0)/2;
        cout<<ans<<endl;
    }else{
        cout<<lst[n/2]<<endl;
    }
}