while 1:
    username = input('请输出您需要注册的账号：')
    password = input('请输出您需要注册的密码：')
    if username.isalnum() and password.isalnum():
        print('可以注册√')
        username_new = input('请再次确认您需要注册的账号：')
        password_new = input('请再次确认您需要注册的密码：')
        if username_new == username and password_new == password:
            print('注册成功！')
            break
    else:
        input('注册信息有误，请重新输入\n')

username_file = open('Username', mode='a', encoding='utf-8')
password_file = open('Password', mode='a', encoding='utf-8')

username_file.write(username)
password_file.write(password)
username_file.close()
password_file.close()

for i in range(3):
    login_username = input('请登录用户名：')
    login_password = input('请登录密码：')
    username = open('Username', mode='r', encoding='utf-8')
    password = open('Password', mode='r', encoding='utf-8')
    read_user = username.read()
    read_pass = password.read()
    if login_username == read_user and login_password == read_pass:
        print('登录成功！')
        break
    else:
        ii = i + 1
        num = 3 - ii
        print('登录失败，请重新登录！您还剩余{}次数'.format(num))
else:
    print('账号已锁定！')