python 验证输入的帐号和密码

原玛：

username=input("nput username:")
password=input("input password:")

print(username)
print(password)

num=0
flag=0

while True:
    usr=input("input username:")
    if usr==username:
        while num<3:
            word=input("input password:")
            if password==word:
                print("Success")
                flag=1
                break
            else:
                num+=1
                if num<=2:
                    print("password error,again")
        if flag==1:
            break
        num=0
        print("password error three times, input again.")
    else:
        print("username error!")

运行结果：