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>

int main(void){
  int K,N,a;
  scanf("%d %d",&N,&K);
  if(K==1 || K>10){
    printf("Kの値は１＜K＜１１です。\n");
    exit(1);
  }
  a=N;
  for(int i=1;i<N+1;i++){
    a=a/K;
    if(a<K){
      printf("%d\n",i+1);
    break;
    }
  }
  
  return 0;
}