#include <iostream>
#include <iomanip>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n;
    while (cin >> n) {
        double year = 0;
        double student;
        for (int i = 0; i < n; i++) {
            cin >> student;
            year += student;
        }
        year = year / n;
        cout << fixed << setprecision(2) << year << "\n";
    }
    return 0;
}