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;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Console = System.Console;

namespace Atcoder
{
    class Program
    {

        static void Main(string[] args)
        {
            var r = ReadIntArray();
            var N = r[0];
            var K = r[1];

            string ret = string.Empty;
            while (N > 0)
            {
                ret += N % K;
                N /= K;
            }

            Console.WriteLine(ret.Length);
        }
        private static readonly Func<string> Read = () => Console.ReadLine();
        private static readonly Func<string[]> ReadStringArray = () => Console.ReadLine().Split();
        private static readonly Func<int> ReadInt = () => int.Parse(Console.ReadLine());
        private static readonly Func<long> ReadLong = () => long.Parse(Console.ReadLine());
        private static readonly Func<int[]> ReadIntArray = () => Console.ReadLine().Split().Select(int.Parse).ToArray();
        private static readonly Func<long[]> ReadLongArray = () => Console.ReadLine().Split().Select(long.Parse).ToArray();
        private static readonly Action<string> Cw = str => Console.WriteLine(str);
    }
}