time = 0

login_success = False

USER_NAME = "alex"

PWD = "alex123"

CHECK_CODE = "123"

while time < 4:

    user_name = input("请输入您的用户名： ")

    pwd = input("请输入您的密码： ")

    if user_name == USER_NAME:

        if pwd == PWD:

            print("恭喜您登录成功")

            login_success = True

            break

        else:

            print('您的用户名或密码错误，请重新输入')

            time = time + 1

    else:

        print("您的用户名或密码错误，请重新输入")

        time = time + 1

if not login_success:

    while True:

        check_code = input('请输入验证码： ')

        user_name = input("请输入您的用户名： ")

        pwd = input("请输入您的密码： ")

        if check_code == CHECK_CODE:

            if user_name == USER_NAME:

                if pwd == PWD:

                    print("恭喜您登录成功")

                    break

                else:

                    print("您的用户名或密码错误，请重新输入")

            else:

                print("您的用户名或密码错误，请重新输入")

        else:

            print("验证码错误，重新输入")