Calculate Euler's totient function phi(m). Euler's so-called totient function phi(m) is defined as the number of positive integers r (1 <= r < m) that are coprime to m.

# # # THIS IS A STUB # # #

Example in Elm:
import Html exposing (text)
import List

f : Int -> Int
-- your implementation goes here

main = text (toString (f 0))

Result:

4

Solutions