import java.util.Scanner;

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

        try {
            // Read student type
            if (!scanner.hasNextLine()) {
                System.out.println("Invalid input");
                return;
            }
            String studentType = scanner.nextLine().trim();
            if (!studentType.equals("Undergraduate") && !studentType.equals("Postgraduate")) {
                System.out.println("Invalid input");
                return;
            }

            // Read name
            if (!scanner.hasNextLine()) {
                System.out.println("Invalid input");
                return;
            }
            String name = scanner.nextLine().trim();
            if (name.isEmpty()) {
                System.out.println("Invalid input");
                return;
            }

            // Read ID
            if (!scanner.hasNextLine()) {
                System.out.println("Invalid input");
                return;
            }
            String idLine = scanner.nextLine().trim();
            if (idLine.isEmpty()) {
                System.out.println("Invalid input");
                return;
            }
            // Optionally validate ID format if needed. For now just non‑empty is enough.

            // Read number of grades
            if (!scanner.hasNextLine()) {
                System.out.println("Invalid input");
                return;
            }
            String gradesCountLine = scanner.nextLine().trim();
            int numGrades;
            try {
                numGrades = Integer.parseInt(gradesCountLine);
            } catch (NumberFormatException e) {
                System.out.println("Invalid input");
                return;
            }
            // The spec says “grades must be valid integers between 0 and 100”
            // It doesn't explicitly disallow zero grades, but sample uses positive count
            if (numGrades < 0) {
                System.out.println("Invalid input");
                return;
            }

            double sum = 0.0;
            for (int i = 0; i < numGrades; i++) {
                if (!scanner.hasNextLine()) {
                    System.out.println("Invalid input");
                    return;
                }
                String gradeLine = scanner.nextLine().trim();
                int grade;
                try {
                    grade = Integer.parseInt(gradeLine);
                } catch (NumberFormatException e) {
                    System.out.println("Invalid input");
                    return;
                }
                if (grade < 0 || grade > 100) {
                    System.out.println("Invalid input");
                    return;
                }
                sum += grade;
            }

            // If all inputs valid, compute average and print with two decimal places
            // If no grades (numGrades == 0), average is 0.00 (you can adjust if different behavior desired)
            double average = (numGrades == 0) ? 0.0 : (sum / numGrades);
            System.out.printf("%.2f%n", average);

        } finally {
            scanner.close();
        }
    }
}