Hello and welcome to the challenge!
Write a code which checks how many proper fractions you can make using the given number
d as a denominator. By a proper fraction we consider such a fraction
GCD(n,d) = 1 (where GCD stands for greatest common divisor).
solve(1) -> 0
solve(2) -> 1
solve(15) -> 8
- the given number
- the amount of proper fractions we can make using the given number
das a denominator
Have fun and good luck! :)