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 C (Clang 3.8.0) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h>
#pragma warning(disable : 4996) //_CRT_SECURE_NO_WARNINGS

int calc(long n, long k,int cnt) {
	if (n < k)return cnt+1;
	return calc(n / k, k, cnt+=1);
}

int main(void) {
	long n, k;
	int cnt = 0;
	scanf("%ld%ld", &n, &k);
	printf("%d",calc(n,k,cnt));
	return 0;
}