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.IO;
using System.Linq;

namespace AtCorder
{
    public static class Program
    {
        static public void Main(string[] args)
        {
            int output = 1;
            int[] input = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int num = input[0];
            while (true)
            {
                if (input[0] < input[1])
                {
                    break;
                }
                if (num / input[1] >= input[1])
                {
                    output++;
                    num = num / input[1];
                }
                else 
                {
                    output++;
                    break;
                }

            }
            
            Console.WriteLine(output.ToString());
        }
    }
}