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

int main(){
	int n;
	double res;
	cin >> n;
	vector<int> v(n);
	for(int i =0; i < n; i++){
		cin >> v[i];
	}

	sort(v.begin(), v.end());
	if(n%2 == 1) res = v[n/2];
	else res = (double)(v[n/2-1] + v[n/2])/2;
	cout << res << endl;
}