diy2.py

i=3
username = "python"
userpassword = "123456"
while True:
    if i>0:
        name = input("请输入用户名:")
        password = input("请输入密码:")
        i=i-1
        if name == username and password == userpassword:
            print("登录成功!")
            break
        if name != username:
            print("用户名有误")
            continue
        if password != userpassword:
            print("密码有误")
    else:
        print("请拿身份到我们银行解冻")
        exit()
print("欢迎进入我们系统")