I chose to solve this with a binary search knowing that the result of integer division x/y where y is in our control and y>x then x//y == 0 and g^0 = 1 tells us the magnitude of the flag.

Full writeup:

https://ctf.rip/write-ups/crypto/corctf-dividing-secrets/

Original writeup (https://ctf.rip/write-ups/crypto/corctf-dividing-secrets/).