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: Wrong Answer)

using System;
class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            long se = long.Parse(s.Split(' ')[0]);
            long sinnsuu = int.Parse(s.Split(' ')[1]);

            int i = 1;
            long l = 1;
            while (true)
            {
                l = 1;
                for (int a = 0; a != i; a++)
                {
                    l *= sinnsuu;
                }
                if (l < se)
                {
                    i++;
                }
                else
                {
                    break;
                }
            }
            if(sinnsuu == 10)
            {
                i += 1;
            }
            Console.WriteLine(i);
            Console.ReadLine();
        }
    }