#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n;i>=0;i--)
#define FOR(i,m,n) for(int i=m;i<n;i++)
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
using namespace std;
typedef long long ll;
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
//const ll INF = 1LL << 60;
//const int INF = 1001001001;
const ll mod = 1000000007;

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