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>
#include <math.h>

int main(){
  int N,K;
  scanf("%d%d",&N,&K);
  
  int ketasu = 0;
  for(int i=0; i<100; i++){
    if(N > power(K,i)){
      ketasu++;
    }else{
      break;
    }
  }
  printf("%d",ketasu);
}

int power(int K, int i){
  int sum = 1;
  if(i == 0){
    return 1;
  }else{
    for(int j=1; j<=i; j++){
      sum *= K;
    }
  }
  return sum;
}