#include <bits/stdc++.h>
int compare(const void *a, const void *b) {
  int c = *(int *)a;
  int d = *(int *)b;
  return c - d;
}
int main() {
  static int v[50];
  int n, i;
  float p;
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%f", &v[i]);
  qsort(v, n, sizeof *v, compare);
  for (i = 1; i < n; i++) {
    printf("%.1f", v[i]);
  }
  p = v[0];
  for (i = 1; i < n; i++) p = (p + v[i]) / 2;
  printf("%f\n", p);
  return 0;
}
