Simplify the f function and use bruteforce to recover the flag.
Solver code: [https://github.com/CTF-STeam/ctf-writeups/blob/master/2020/COMPFEST/i-hope-it-is-easy/solve.py](https://github.com/CTF-STeam/ctf-writeups/blob/master/2020/COMPFEST/i-hope-it-is-easy/solve.py)
Flag: `COMPFEST12{ez_pz_lemonade_squeez_a42447}`