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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;

public class ABC156_B {
    private static void Main(string[] args) {
        var inputs = Console.ReadLine().Trim().Split();
        var n = int.Parse(inputs[0]);
        var k = int.Parse(inputs[1]);

      	var logKN = Math.Log(n, k);
      	var answer = (logKN == (int)logKN) ? ((int)logKN + 1) : Math.Ceiling(logKN);
        Console.WriteLine(answer);
    }
}