import java.util.\*;
import java.util.stream.\*;

class Product {
    String name;
    String category;
    double price;

    Product(String name, String category, double price) {
        this.name = name;
        this.category = category;
        this.price = price;
    }
}

class Order {
    String orderId;
    List<Product> products;

    Order(String orderId, List<Product> products) {
        this.orderId = orderId;
        this.products = products;
    }

    double getTotalAmount() {
        return products.stream()
                .mapToDouble(p -> p.price)
                .sum();
    }
}

class Seller {
    String name;
    List<Order> orders;

    Seller(String name, List<Order> orders) {
        this.name = name;
        this.orders = orders;
    }

    List<Order> getOrdersAboveAmount(double amount) {
        return orders.stream()
                .filter(order -> order.getTotalAmount() > amount)
                .collect(Collectors.toList());
    }
}

public class Main {
    public static void main(String[] args) {
        List<Seller> sellers = Arrays.asList(
            new Seller("Alice", Arrays.asList(
                new Order("O1", Arrays.asList(
                    new Product("Laptop", "Electronics", 1000),
                    new Product("Phone", "Electronics", 500)
                )),
                new Order("O2", Arrays.asList(
                    new Product("Shirt", "Clothing", 50),
                    new Product("Jeans", "Clothing", 80)
                ))
            )),
            new Seller("Bob", Arrays.asList(
                new Order("O3", Arrays.asList(
                    new Product("Tablet", "Electronics", 300),
                    new Product("Smartwatch", "Electronics", 200)
                )),
                new Order("O4", Arrays.asList(
                    new Product("Monitor", "Electronics", 150),
                    new Product("Headphones", "Electronics", 80)
                ))
            ))
        );

        sellers.stream()
            .flatMap(s -> s.getOrdersAboveAmount(400).stream()) 
            .flatMap(o -> o.products.stream()) 
            .filter(p -> p.category.equals("Electronics")) 
            .sorted(Comparator.comparingDouble(p -> p.price)) 
            .forEach(p -> System.out.println(p.name)); 
    }
}

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.Scanner;


class User {
    private final int id;
    private final String username;
    private final String password; 
    private int loginAttempts;    

    public User(int id, String username, String password) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.loginAttempts = 0;
    }

    public int getId() {
        return id;
    }
    
    public String getUsername() {
        return username;
    }
    
    public int getLoginAttempts() {
        return loginAttempts;
    }
    
    public boolean validatePassword(String inputPassword) {
        if (this.password.equals(inputPassword)) {
            loginAttempts++;
            return true;
        }
        return false;
    }
}

class UserRepository {
    private final Map<String, User> users = new HashMap<>();
    private int nextId = 1;

    public UserRepository() {
    
        users.put("alice", new User(nextId++, "alice", "password123"));
        users.put("bob", new User(nextId++, "bob", "secure456"));
    }
    
    public Optional<User> findByUsername(String username) {
        return Optional.ofNullable(users.get(username));
    }
    
    public User createUser(String username, String password) {
        User newUser = new User(nextId++, username, password);
        users.put(username, newUser);
        return newUser;
    }
}

class UserService {
    private final UserRepository userRepository;

    public UserService(UserRepository repo) {
        this.userRepository = repo;
    }
    
    public Optional<User> login(String username, String password) {
        return userRepository.findByUsername(username)
                             .filter(user -> user.validatePassword(password));
    }
    
    public Optional<User> register(String username, String password) {
        if (userRepository.findByUsername(username).isPresent()) {
            return Optional.empty();
        }
        User newUser = userRepository.createUser(username, password);

        newUser.validatePassword(password);
        return Optional.of(newUser);
    }
    

    public String getLoginInfo(String username) {
        return userRepository.findByUsername(username)
                             .map(user -> "Количество успешных входов: " + user.getLoginAttempts())
                             .orElse("Пользователь не найден.");
    }
}

public class InteractiveLoginApp {
    public static void main(String[] args) {
        UserRepository userRepository = new UserRepository();
        UserService userService = new UserService(userRepository);
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("Выберите действие: ");
        System.out.println("1. Вход");
        System.out.println("2. Регистрация");
        System.out.print("Ваш выбор (1 или 2): ");
        String choice = scanner.nextLine().trim();
        
        if ("1".equals(choice)) {
            System.out.print("Введите имя пользователя: ");
            String username = scanner.nextLine().trim();
            
            System.out.print("Введите пароль: ");
            String password = scanner.nextLine().trim();
            
        
            Optional<User> userOpt = userService.login(username, password);
            if (userOpt.isPresent()) {
                System.out.println("Вход выполнен успешно! Добро пожаловать, " + username + ".");
                System.out.println(userService.getLoginInfo(username));
            } else {
                System.out.println("Неверное имя пользователя или пароль.");
            }
        } else if ("2".equals(choice)) {
            System.out.print("Введите желаемое имя пользователя: ");
            String username = scanner.nextLine().trim();
            
            System.out.print("Введите пароль: ");
            String password = scanner.nextLine().trim();
            
            Optional<User> userOpt = userService.register(username, password);
            if (userOpt.isPresent()) {
                System.out.println("Регистрация прошла успешно! Добро пожаловать, " + username + ".");
                System.out.println(userService.getLoginInfo(username));
            } else {
                System.out.println("Пользователь с именем " + username + " уже существует. Попробуйте войти.");
            }
        } else {
            System.out.println("Некорректный выбор.");
        }
        
        scanner.close();
    }
}