#include <iostream>
#include <string>
#include <vector>
#include <cstdio>
#include <algorithm>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

int main(void){
	int n; cin >> n;
	vector<double> v(n);
	rep(i, n){
		cin >> v[i];
	}
	sort(v.begin(), v.end());
	if(v.size() % 2 == 0){
		cout << (v[v.size() / 2 - 1] + v[v.size() / 2]) / 2.0 << endl;
	}else{
		cout << (v[v.size() / 2]) << endl;
	}
	return 0;
}