#include <bits/stdc++.h>
using namespace std;
int main() {
  double A;
  cin >> A;
  int X;
  int sum = 0;
  for (int i = 0; i < A; i++) {
    cin >> X;
    sum += X;
  }
  double H = sum / A;
  cout << H / A << endl;
}
