diy2.py

s = 3
username = "python"
userpassword = "123456"
while True:
    if s>0:
        name = input("请输入用户名:")
        password = input("请输入密码:")
        s-=1
        if name == username and password == userpassword:
            print("登录成功!")
            break
        if name != username:
            print("用户名错误!请重新输入")
        if password != userpassword:
            print("密码错误!请重新输入")
    else:
        print("你的手机已经废了，你个大SB,耗子尾汁吧！")
        exit()
print("欢迎来到贝尔编程!")