using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("請輸入使用者名稱：");

        string username,password;

        username = Console.ReadLine();

        if (username == "Angel")

        {

            Console.WriteLine("請輸入密碼");

            password = Console.ReadLine();

            if((password == "egg566")||(password == "EGG566"))

            {

                Console.WriteLine("歡迎進入本系統");   

            }else{

                    Console.WriteLine("密碼錯誤");

            }

        }

            else if(username == "Allen")

            {

                Console.WriteLine(username + "您好");

                Console.WriteLine("請輸入密碼");

                password = Console.ReadLine();

                if((password == "dog123")||(password == "DOG123"))

                {

                Console.WriteLine("歡迎進入本系統");   

                }else{

                    Console.WriteLine("密碼錯誤");

                }       

            }else

            {

                Console.WriteLine("本系統不認識"+username);

                Console.WriteLine("請重新輸入");

            }

    }

}