import java.util.*;

class Student {
    String graduate;
    String name;
    int id;
    int numberOfGrades;
    int[] grades;

    Student(String graduate, String name, int id, int numberOfGrades, int[] grades) {
        this.graduate = graduate;
        this.name = name;
        this.id = id;
        this.numberOfGrades = numberOfGrades;
        this.grades = grades;
    }

    public double average() {
        int sum = 0;
        for (int grade : grades) {
            if (grade < 0 || grade > 100) {
                return -1; 
            }
            sum += grade;
        }
        return (double) sum / numberOfGrades;
    }
}

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

        String graduate = sc.nextLine();  
        int id = sc.nextInt();
        int numberOfGrades = sc.nextInt();
        if (!(graduate.equals("Undergraduate") || graduate.equals("Postgraduate"))) {
            System.out.println("Invalid input");
            return;
        }

        int[] grades = new int[numberOfGrades];
        for (int i = 0; i < numberOfGrades; i++) {
            if (!sc.hasNextInt()) {
                System.out.println("Invalid input");
                return;
            }
            grades[i] = sc.nextInt();
        }

        Student student = new Student(graduate, name, id, numberOfGrades, grades);
        double avg = student.average();

        if (avg == -1) {
            System.out.println("Invalid input");
        } else {
            System.out.printf("%.2f\n", avg);
        }
    }
}