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)

#include <stdio.h>

int ruijou(int, int);

int main() {

    int i;
    int n, k;

    scanf("%d%d", &n, &k);

    for(i = 1; i <= 34; i++) {
        if(n + 1 <= ruijou(i, k)) {
            printf("%d\n", i);
            break;
        }
    }
    
    return 0;
}

int ruijou(int i, int k) {
    int j;
    int x = 1;

    for(j = 0; j < i; j++) {
        x = x * k;
    }
    return x;
}