Negative values with GCD python program

Question

Iam doing GCD tool in python but for some reason every time I use 2 negative values I get back negative value back. Beceause this is for school i cant use things like obs() ort math etc.. Can some help me with that?

from sys import stdin


a = 0
b = 0
a0 = 0
b0 = 0
a1 = 0
b1 = 0
n = 0
na = 0
nb = 0
q = 0

for line in stdin:
    input = line.lstrip().rstrip().split()

    if line == '' or len(input) != 2:
        break

    a, b = [int(x) for x in line.lstrip().rstrip().split()]

    if a > b:

        a, b = b, a


    #
    #     a  | b
    #   +---------+
    # a | 1  | 0  | "( a0, b0 )"
    # b | 0  | 1  | "( a1, b1 )"
    # n | na | nb | q
    #   |    |    |
    #
    #

    a0 = 1
    b0 = 0
    a1 = 0
    b1 = 1

    n = a % b
    q = a / b

    na = a0 - q * a1
    nb = b0 - q * b1
    
    a = b
    a0 = a1
    b0 = b1
    

    b = n
    a1 = na
    b1 = nb
    


    while n != 0:
        n = a % b
        q = a // b
        

        na = a0 + q * a1
        nb = b0 + q * b1

        a = b
        a0 = a1
        b0 = b1

        b = n
        a1 = na
        b1 = nb
   
    print(a)

I tried messing around with operators. I expect to -888 -2 be 2 not -2 (I need to fix the code not to edit results )

Edit 1 : Here are some examples of what i need

Input       Output

7 11        1
888 2       2
905 5       5
-7 11       1
-888 -2     2
905 -5      5