# Write a function gcd(x,y) that finds the greatest common divisor between two nonnegative integers. 
# Algebraically, gcd(x,y) is x if y is zero; it’s gcd(y, rem(x,y)) otherwise.

defmodule MyModule do
    
    def gcd(x,0) do
        x
    end

    def gcd(x,y) do
        gcd(y, rem(x, y))
    end

end

IO.puts MyModule.gcd(17*5, 13*5)