import java.util.Scanner;
class Student {
    String type;
    String name;
    String id;
    int numGrades;
    int[] grades;
    Student(String type, String name, String id, int numGrades, int[] grades) {
        this.type = type;
        this.name = name;
        this.id = id;
        this.numGrades = numGrades;
        this.grades = grades;
    }
    String calculateAverage() {
        if (!(type.equals("Undergraduate") || type.equals("Postgraduate"))) {
            System.out.println("Invalid input");
            return;
        }

        int sum = 0;
        for (int grade : grades) {
            if (grade < 0 || grade > 100) {
                return "Invalid input";
            }
            sum += grade;
        }

        double avg = (double) sum / numGrades;
        return String.format("%.2f", avg);
    }
}
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String type = sc.nextLine();
        String name = sc.nextLine();
        String id = sc.nextLine();
        int numGrades = Integer.parseInt(sc.nextLine());

        int[] grades = new int[numGrades];
        for (int i = 0; i < numGrades; i++) {
            grades[i] = Integer.parseInt(sc.nextLine());
        }

        Student student = new Student(type, name, id, numGrades, grades);
        System.out.println(student.calculateAverage());
    }
}