Help me in solving LCM_GCD problem

help
,
1

My issue

i got time limit exist what i am do now

My code

# cook your dish here
from math import gcd, lcm
def min_lcm_gcd(a, b):
    min_diff = float('inf')
    for d in range(1, b+1):
        if b % d == 0:
            curr_diff = lcm(a, d) - gcd(b, d)
            min_diff = min(min_diff, curr_diff)
    return min_diff
Tharun = int(input())
for _ in range(Tharun):
    a, b = map(int, input().split())
    print(min_lcm_gcd(a, b))

Learning course: Roadmap to 3*
Problem Link: https://www.codechef.com/learn/course/klu-roadmap-3star/KLURMP301/problems/LCM_GCD