Minor tweak to code that calculates cube root in challenge 40
Minor tweak to code that calculates cube root in challenge 40

In my tests, it works reliably if the precision is len(str(cube)) // 3
+ 3. I added 1 to be safe. Some day, I may try to come up with a more
rigorously-derived number, but that is not a top priority.

mikez302/cryptopals_solutions,mikez302/matasanoSolutions