Problem:
Score : 200 points

Problem Statement

Given is an integer N. Find the number of digits that N has in base K.

Notes

For information on base-K representation, see Positional notation - Wikipedia.

Constraints

All values in input are integers.

1 \leq N \leq 10^9

2 \leq K \leq 10

Input

Input is given from Standard Input in the following format:

N K

Output

Print the number of digits that N has in base K.

Sample Input 1

11 2

Sample Output 1

4

In binary, 11 is represented as 1011.

Sample Input 2

1010101 10

Sample Output 2

7

Sample Input 3

314159265 3

Sample Output 3

18

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

import Data.List
-- n を k 進数
solve t n = loop t 0 
    where
        loop :: Int -> Int -> [Int]
        loop t i
            | t == 0 = []
            | otherwise =
                let
                    (t', k) = quotRem t n
                in
                    k : loop t' (i+1)

main = do
    [n, k] <- map read . words <$> getLine :: IO [Int]
    print $ length $ solve n k