#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());
	cout<<(n%2==0?(double)(a[n/2]+a[n/2-1])/2:(double)a[n/2])<<endl;
	return 0;
}