Python 3.4.3：NameError

Question

我的程序给出了一个NameError。这个错误让我困扰了很长一段时间，如果有人帮我回答，我会很感激。

Please input the first number: 30
Please input the second number: 6
Traceback (most recent call last):
  File "/Users/2019_coen_ploeger/Documents/HS/Grade 9/Programming/Chapter 3/Project 3/Gcd.py", line 21, in <module>
    if num1%div==1:
NameError: name 'div' is not defined

它背后的程序是。

num1=int(input('Please input the first number: '))
    num2=int(input('Please input the second number: '))
    #
    if num1%div==1:
        while div <= num1:
            while div <= num2:
                print(d)
    else:
        div-=1