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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;

public class Main {

	@SuppressWarnings("resource")
	void run() {

		//
		// 画面入力
		//
		Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
    	int k = sc.nextInt();

    	int digit = 0;
    	for(int i = 0; n - Math.pow(k, i) > 0; i++){
    		digit = i + 1;
    	}
    	System.out.println(digit);

	}
	
    public static void main(String[] args) {
        new Main().run();
    }
}