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

int main(){
	int n;
	cin >> n;
	vector<int> data(n);
	for(auto &a:data) cin >> a;
	sort(data.begin(),data.end());
	cout << (n%2 ? data[n/2] : double((data[n/2] + data[n/2-1]) / 2.0)) << endl;
	/*
	if(n % 2 != 0){
		cout << double((data[n/2] + data[n/2+1]) / 2.0) << endl;
	}else{
		cout << data[n/2] << endl;
	}
	*/
	return 0;
}