#include <bits/stdc++.h>
using namespace std;
int main() {
  double p, total, portion;
  int i, n;
  while (scanf("%d", &n) == 1) {
    portion = 100.0 / (double)n;
    total = 0.0;
    for (i = 1; i <= n; i++) {
      scanf("%lf", &p);
      total += ((p * portion) / 100.0);
    }
    printf("%lf\n", total);
  }
  return 0;
}
