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

public class avereg {
    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++) {
            sum += Double.parseDouble(entry1.nextLine());
            //sum = sum + numbers;
            //result = sum / n;
        }
        double result = sum/n;
        System.out.print(df2.format(result));
        //System.out.printf()
    }
}