#include<fstream>
#include<iostream>
#include<iomanip>
#include<set>
using namespace std;

//ifstream f("1306.in");

struct cmp
{	bool operator()(unsigned int a, unsigned int b)
	{	return a > b;
	}
};

int N;
multiset<unsigned int, cmp> h;

int main()
{	int i, j;
	double rez;

	cin>>N;
	for(i = 1; i <= N; i++)
	{	cin>>j;
		if(i > N / 2 + 1)
		{	if(j < *h.begin())
				h.erase(h.begin()), h.insert(j);
		}else h.insert(j);
	}

	if(N % 2) rez = *h.begin();
	else
	{	rez = *h.begin();
		h.erase(h.begin());
		rez += *h.begin();
		rez /= 2;
	}

	cout.precision(1);
	cout<<fixed<<rez<<'\n';

	//f.close();
	return 0;
}