// import java.util.*;
// public class Main
// {
//     public static void main(String[] args)
//     {
//         Scanner sc = new Scanner(System.in);
//         String studentType = sc.nextLine().trim();
//         if (!(studentType.equals("Undergraduate") || studentType.equals("Postgraduate")))
//         {
//             System.out.println("Invalid input");
//             return;
//         }
//         String name = sc.nextLine().trim();
//         String id = sc.nextLine().trim();
//         int n = sc.nextInt();
//         int sum = 0;
//         for (int i = 0; i < n; i++)
//         {
//             int grade = sc.nextInt();
//             if (grade < 0 || grade > 100)
//             {
//                 System.out.println("Invalid input");
//                 return;
//             }
//             sum += grade;
//         }
//         double avg = (double) sum / n;
//         System.out.printf("%.2f\n", avg);
//     }
// }


import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String studentType = sc.nextLine().trim();
        if (!(studentType.equals("Undergraduate") || studentType.equals("Postgraduate"))) {
            System.out.println("Invalid input");
            return;
        }

        String name = sc.nextLine().trim();
        String id = sc.nextLine().trim();

        int n;
        try {
            n = Integer.parseInt(sc.nextLine().trim());
        } catch (Exception e) {
            System.out.println("Invalid input");
            return;
        }

        if (n <= 0) {
            System.out.println("Invalid input");
            return;
        }

        int sum = 0;
        for (int i = 0; i < n; i++) {
            String line = sc.nextLine().trim();
            int grade;
            // try {
            //     grade = Integer.parseInt(line);
            // } catch (Exception e) {
            //     System.out.println("Invalid input");
            //     return;
            // }

            if (grade < 0 || grade > 100) {
                System.out.println("Invalid input");
                return;
            }
            sum += grade;
        }

        double avg = (double) sum / n;
        System.out.printf("%.2f\n", avg);
    }
}