#include <algorithm>
#include <vector>
#include <cfloat>
#include <string>
#include <cmath>
#include <set>
#include <cstdlib>
#include <map>
#include <ctime>
#include <iomanip>
#include <functional>
#include <deque>
#include <iostream>
#include <cstring>
#include <queue>
#include <cstdio>
#include <stack>
#include <climits>
#include <sys/time.h>
#include <cctype>

using namespace std;

typedef long long ll;

int main() {
  int n;
  scanf("%d", &n);
  double a[n];
  for (int i = 0; i < n; i++) {
    scanf("%lf", &a[i]);
  }
  sort(a, a+n);
  if (n%2) {
    printf("%lf\n", a[n/2]);
  }else {
    printf("%lf\n", (a[n/2-1]+a[n/2])/2.);
  }
}