diy2.py

username = "python"
userpassword = "123456"
i=3
while True:
    if i>0:
        name = input("请输入用户名:")
        password = input("请输入密码:")
        i-=1
        if name == username and password == userpassword:
            print("登录成功!")
            break
        if name != username:
            print("请再输入用户名")
            continue
        if userpassword != password:
            print("请再输入密码")
    else: 
        print("Fuck you!!!!!!!!!!!!!!!!!!")
        exit()  
print("欢迎来到贝尔编程!")