#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <math.h>
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REP1(i, n) for (ll i = 1; i <= n; i++)
#define RREP(i, n) for (ll i = n - 1; i >= 0; i--)
#define RREP1(i, n) for (ll i = n; i >= 1; i--)
#define FOR(i, a, b, c) for (ll i = a; i <= b; i += c)
#define RFOR(i, a, b, c) for (ll i = a; i >= b; i -= c)
#define MAX(a, b) (a > b ? a : b)
#define MIN(a, b) (a < b ? a : b)
#define SORT(t, a, n) qsort(a, n, sizeof(t), ({ int f (const void *a, const void *b) { return *(t *)a - *(t *)b; } f; }));
#define RSORT(t, a, n) qsort(a, n, sizeof(t), ({ int f (const void *a, const void *b) { return *(t *)b - *(t *)a; } f; }));
#define SUM(t, a, n) ({ t s = 0; REP(i, n) s += a[i]; s; })
#define CNT(t, x, a, n) ({ t c = 0; REP(i, n) if (a[i] == x) c++; c; })
#define INF 1145141919
typedef long long ll;

int main() {
    int n;
    scanf("%d", &n);
    int a[1000];
    REP(i, n) scanf("%d", &a[i]);
    
    SORT(int, a, n);
    double ans;
    if (n % 2) ans = a[n / 2];
    else ans = (a[n / 2 - 1] + a[n / 2]) / 2.0;
    printf("%llf\n", ans);
    return 0;
}