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 Python (3.4.3) (judge verdict: Accepted)

from collections import deque, Counter as cnt
from collections import defaultdict as dd
from operator import itemgetter as ig
from bisect import bisect_right as bsr
from math import factorial, ceil, floor
import sys
sys.setrecursionlimit(1000000)

# お約束
args = None
INF = float("inf")
MOD = int(1e9 + 7)


def input(*ps):
    if type(ps[0]) is list:
        return [input(*ps[0][:-1]) for _ in range(ps[0][-1])]
    elif len(ps) == 1:
        return ps[0](next(args))
    else:
        return [p(next(args)) for p in ps]


def nlist(n, v):
    if not n:
        return [] if type(v) is list else v
    return [nlist(n[1:], v) for _ in range(n[0])]


def yesno(v):
    print(["Yes", "No"][not v])


def main():
    """エントリーポイント"""
    N, K = input(int, int)
    n = N
    ans = 0
    while 0 < n:
        n //= K
        ans += 1
    print(ans)


if __name__ == '__main__':
    args = iter(sys.stdin.read().split())
    main()