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