#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());
    float ans=(n%2==0?(a[n/2-1]+a[n/2])/2.0:a[n/2]);
    cout<<fixed<<setprecision(1)<<ans<<endl;
}