import java.util.Scanner;

class Node {
    int data;
    Node next;

    public Node(int data) {
        this.data = data;
        this.next = null;
    }
}

class SinglyLinkedList {
    private Node head;

    public void create(int data) {
        head = new Node(data);
        System.out.println("Linked List created with head node: " + data);
    }

    public void insert(int data) {
        Node newNode = new Node(data);
        if (head == null) {
            head = newNode;
        } else {
            Node temp = head;
            while (temp.next != null) {
                temp = temp.next;
            }
            temp.next = newNode;
        }
        System.out.println("Node inserted: " + data);
    }

    public void delete(int data) {
        if (head == null) {
            System.out.println("List is empty. Nothing to delete.");
            return;
        }
        if (head.data == data) {
            head = head.next;
            System.out.println("Node deleted: " + data);
            return;
        }
        Node temp = head;
        while (temp.next != null && temp.next.data != data) {
            temp = temp.next;
        }
        if (temp.next == null) {
            System.out.println("Node not found: " + data);
        } else {
            temp.next = temp.next.next;
            System.out.println("Node deleted: " + data);
        }
    }

    public void display() {
        if (head == null) {
            System.out.println("List is empty.");
            return;
        }
        Node temp = head;
        System.out.print("Linked List: ");
        while (temp != null) {
            System.out.print(temp.data + " -> ");
            temp = temp.next;
        }
        System.out.println("NULL");
    }
}

public class LinkedListMenu {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        SinglyLinkedList list = new SinglyLinkedList();
        
        while (true) {
            System.out.println("\nMenu:");
            System.out.println("1. Create Linked List");
            System.out.println("2. Insert Node");
            System.out.println("3. Delete Node");
            System.out.println("4. Display List");
            System.out.println("5. Exit");
            System.out.print("Enter your choice: ");
            
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    System.out.print("Enter data for head node: ");
                    int data = scanner.nextInt();
                    list.create(data);
                    break;
                case 2:
                    System.out.print("Enter data to insert: ");
                    data = scanner.nextInt();
                    list.insert(data);
                    break;
                case 3:
                    System.out.print("Enter data to delete: ");
                    data = scanner.nextInt();
                    list.delete(data);
                    break;
                case 4:
                    list.display();
                    break;
                case 5:
                    System.out.println("Exiting program.");
                    scanner.close();
                    return;
                default:
                    System.out.println("Invalid choice. Try again.");
            }
        }
    }
}