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: Accepted)

/*ex3_3
series2*/
 
# include <stdio.h>
int main(void){
      //各文字の箱を作って読み取り
    int N,K;
    scanf("%d %d", &N,&K);
    int i=0;//桁数
    int j=1;//現在の調べている位を十進法で表した時の値
    while(j<=N){
        //現在の調べている位を十進法で表した時の値が調べている数字Nを超えたとき、その時のiは桁数になる。
        j=j*K;
        i ++;
    }
    printf("%d\n",i);
    return 0;
}