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;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {

            int[] iarray = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();
            int N = iarray[0];
            int K = iarray[1];
            string val = Sinsu(N, K, "");
            Console.WriteLine(val.Length);

        }

        public static string Sinsu(int n, int k, string str)
        {
            str = n % k + str;
            n /= k;
            if (n != 0)
                return Sinsu(n, k, str);
            return str;
        }
    }
}