#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(void){
//input
	int N;
	cin >> N;
	
	vector<int> a(N);
	for(int i=0;i<N;i++){ cin >> a.at(i); }
//calc
	double ans;
	
	sort(a.begin(),a.end());
	
	if(a.size() % 2 != 0){
		ans = (double)a.at(a.size() / 2);
	}else{
		ans = (double)(a.at(a.size() / 2) + a.at(a.size() / 2 - 1)) / 2;
	}
//output
	cout.precision(3);
	cout << ans;
}