using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using static System.Console;
using static System.Math;

namespace CP
{
    class Atria
    {
        static void Main(string[] args)
        {
            int q = int.Parse(ReadLine());
            for (int i = 0; i < q; i++)
            {
                long[] s = ReadLine().Split(' ').Select(long.Parse).ToArray();
                if (s[1] == 1)
                {
                    WriteLine(s[0]-1);
                    continue;
                }
                long ans = 0;
                long now = 1;
                while (s[0] - now > 0)
                {
                    now *= s[1];
                    ans++;
                }
                WriteLine(ans);
            }

        }
    }
}