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: Accepted)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			// 整数の入力
			int n = sc.nextInt();
			int k = sc.nextInt();
			final String base36 = Integer.toString(n, k);
			System.out.println(base36.length());
		}
	}

	/**
	 * 最小公倍数
	 */
	static long lcm(long a, long b) {
		long temp;
		long c = a;
		c *= b;
		while ((temp = a % b) != 0) {
			a = b;
			b = temp;
		}
		return c / b;
	}

	/**
	 * 最大公約数
	 */
	static long gcd(long a, long b) {
		long temp;
		while ((temp = a % b) != 0) {
			a = b;
			b = temp;
		}
		return b;
	}
}