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;
using System.Collections.Generic;
using System.Linq;

class Abc156b
{
    static int n, k;

    static void Solve()
    {
        // var t = Math.Ceiling(Math.Log(n) / Math.Log(k));
        // System.Console.WriteLine(t);
        var i = 2;
        var t = k;
        while(true){
            if(n >= t){
                ++i;
                t*=k;
            }
            else
                break;
        }

        System.Console.WriteLine(i-1);
    }

    static void Scan()
    {
        var buf = Console.ReadLine().Split();
        n = int.Parse(buf[0]);
        k = int.Parse(buf[1]);
    }

    static void Main()
    {
        Scan();
        Solve();
    }
}