02. SoftUni Party

package Lekciq;

import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

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


        // Sets for VIP and regular guests
        Set<String> vipGuests = new HashSet<>();
        Set<String> regularGuests = new HashSet<>();


        // Reading reservation numbers until "PARTY"
        String input = scanner.nextLine();
        while (!input.equals("PARTY")) {
            if (Character.isDigit(input.charAt(0))) {
                vipGuests.add(input);
            } else {
                regularGuests.add(input);
            }
            input = scanner.nextLine();
        }

        // Reading arrival of guests until "END"
        input = scanner.nextLine();
        while (!input.equals("END")) {
            vipGuests.remove(input);
            regularGuests.remove(input);
            input = scanner.nextLine();
        }

        // Output the guests who didn't come
        int totalNoShows = vipGuests.size() + regularGuests.size();
        System.out.println(totalNoShows);

        // VIP guests first
        TreeSet<String> sortedVipGuests = new TreeSet<>(vipGuests);
        TreeSet<String> sortedRegularGuests = new TreeSet<>(regularGuests);

        sortedVipGuests.forEach(System.out::println);
        sortedRegularGuests.forEach(System.out::println);
    }
}