#include <bits/stdc++.h>
#define rep(i,a,b) for(int i = (a); i < (b); i++)
#define all(A) (A).begin(),(A).end()
#define MOD 1000000007
using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;

int main() {
	int n; cin >> n;
	vector<double> A(n); rep(i,0,n) cin >> A[i];
	sort(all(A));
	cout << fixed << setprecision(10) << (n%2 == 0 ?(A[n/2]+A[n/2-1])/2 : A[n/2]);
}