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 Java7 (OpenJDK 1.7.0) (judge verdict: Wrong Answer)

import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		int n = 0;
		int k = 0;
		ArrayList<Integer> anser = new ArrayList<>();

		Scanner scan = new Scanner(System.in);

		n = scan.nextInt();
		k = scan.nextInt();

		while(n>k) {
			anser.add(n%k);
			n=n/k;
		}

		if(n<k) {
			anser.add(n);
		}
		System.out.println(anser.size());
	}

}