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 
　　　　　sachiyan*/

#include <stdio.h>
#include<math.h> //math.h の標準ライブラリを使用
int main(void){
    int N, K, ans; //入力値N,Kと答えansを定義
    scanf("%d %d", &N, &K); //入力値N,Kを読み取る
    ans = 0; //ansに初期値0を代入
    while(pow(K, ans) <= N){ //powはmath.hによる累乗を計算する関数
        ans++;  //K進数の最高位を探す　Kのans乗がN以下の時はそれ以上の桁が存在するので繰り返す
    }
    printf("%d\n", ans); //答えansを出力
    return 0;
}