using System;

public class Program

{

    public static void Main()

    {

        Console.Write("請輸入使用者名稱:");

        string username,password;

        username=Console.ReadLine();

        if(username=="馬壯")

       {

        Console.WriteLine(username+"您好");

        Console.Write("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=="徐強")

        {

        Console.WriteLine(username+"您好");

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

        }

    }

}