'Looks like you've solved it'

From the description,

A digital root is the recursive sum of all the digits in a number. Given n, take the sum of the digits of n. If that value has two digits, continue reducing in this way until a single-digit number is produced

What does your function return for, say, 195?

Firstly you're not returning the string just printing it, Secondly if c > 0 does not make sense with the statements under them. Hopefully this is enough to guide you through your answer :)