#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007

using namespace std;


int main(void) {
	int n;
	int a[1001];
	double sum;
	
	cin >> n;
	FOR(i, 1, n) {
		cin >> a[i];
	}
	sort(a, a + n + 1);
	if (n % 2 == 0) {
		sum = ((double)a[n / 2] + (double)a[n / 2 + 1]) / (double)2;
	}
	else {
		sum = (double)a[n / 2 + 1];
	}
	printf("%10.5lf\n", sum);
	return 0;
}