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: Accepted)

import java.util.Scanner;
 

//result = Math.pow(num1, num3)
//StringBuffer str = new StringBuffer(hoge1);
//String hoge2 = str.reverse().toString();
public class Main {
	private static Scanner sc = new Scanner(System.in);
	static void p(String ans) {System.out.println(ans);};
	static void p(int ans) {System.out.println(ans);};
	static void p(long ans) {System.out.println(ans);};
	//static String eikomoji[]={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
	
	
	public static void main(String[] args) {
	long N =sc.nextInt();
	long R =sc.nextInt();
	long g=0;
	boolean a=true;
		for(int d=0;a;d++) {
			g+=(long)Math.pow(R, d)*(R-1);
			if(g>=N) {
					p(d+1);
					a=false;
				}
			
		}
		
		
	}
}