import java.text.DecimalFormat;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        DecimalFormat df2 = new DecimalFormat("0.00");
        Scanner entry1 = new Scanner(System.in);
        Scanner entry2 = new Scanner(System.in);


        double n = Double.parseDouble(entry1.nextLine());
        double numbers;
        double sum = 0;
        double result = 0;

        for (int i = 1; i <= n; i++) {
            numbers = Double.parseDouble(entry2.nextLine());
            sum = sum + numbers;
            result = sum / n;
        }

        System.out.print(df2.format(result));

    }
}