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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<stdlib.h>
#define BUFSIZE 10000
#include<math.h>
int N,K,m=1;

int cal(int n,int k){
	
	if(n/k >= k){
		m++;
		cal(n/k,k);
	}else{
		return m-1;
	}
}

int main(void){
	scanf(" %d",&N);
	scanf(" %d",&K);
	
		cal(N,K);
	printf(" %d",m+1);
}