Write the function getKthDigit(n, k) that takes a possibly-negative int n and a non-negative int k, and returns the kth digit of n, starting from 0, counting from the right. So:

getKthDigit(789, 0) == 9
getKthDigit(789, 1) == 8
getKthDigit(789, 2) == 7
getKthDigit(789, 3) == 0
getKthDigit(-789, 0) == 9