The function addDigits(n) takes one argument, n, which is a positive integer, and returns the sum of all the digits in n.

Here are two example calls to the function:

addDigits(123) # returns 6 addDigits(40305) # returns 12 

You must write the function recursively. You may not have for or while loops in your code, nor may you convert to a string. You must complete this using only mathematical operations.

Hint: the mod and integer divide operators are your friends