import java.util.Scanner;

public class Program9A {
    private static int maxNumberStudents = 0;
    private static int actualNumberStudents = 0;
    private static String[] studentNames;

    public static void main(String[] args) {
        System.out.print("Please enter the maximum number of students: ");
        Scanner input = new Scanner(System.in);
        maxNumberStudents = input.nextInt(); //Gets input from the user.
        studentNames = new String[maxNumberStudents];
        enterStudentNames(studentNames);
        printStudentNames(studentNames);
        sortStudentNames(studentNames);
    }

    public static void enterStudentNames(String[] studentNames) {
        Scanner nameInput = new Scanner(System.in);

        for (actualNumberStudents = 0; actualNumberStudents < maxNumberStudents; actualNumberStudents++) {
            System.out.print("First name (enter period . to quit): ");
            String firstName = nameInput.next();
            if (firstName.equals(".")) {
                break;
            }
            System.out.print("Last name: ");
            String lastName = nameInput.next();
            String fullStudentName = lastName + ", " + firstName;
            studentNames[actualNumberStudents] = fullStudentName;
        }
    }

    static void printStudentNames(String[] list) {
        for (int i = 0; i < actualNumberStudents; i++) {
            if (list[i].isEmpty() || list[i] == null) {
                break; //Stops the program if a null is read.
            }
            System.out.printf("%d. %s\n", i+1, list[i]);

        }
    }
    public static void sortStudentNames(String[] studentNames) {
        int j;
        String temp;
        for (j = 0; j < actualNumberStudents; j++)
        {
            for (int i = j + 1; i < actualNumberStudents; i++) {
                if (studentNames[j].compareTo(studentNames[i]) > 0) {
                    temp = studentNames[j];
                    studentNames[j] = studentNames[i];
                    studentNames[i] = temp;
                }
            }
            System.out.printf("\n%d. %s", j+1, studentNames[j]);
        }
    }
}