#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, k, sum = 0.0;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> k;
    sum += k;
  }
  cout << fixed << setprecision(12) << sum / n << endl;
  return 0;
}
