using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Globalization;

namespace _1484Kino
{
    class Program
    {
        static void Main(string[] args)
        {
            var userInput = Console.ReadLine().Split();
            var x = double.Parse(userInput[0],CultureInfo.InvariantCulture);
            var y = double.Parse(userInput[1], CultureInfo.InvariantCulture);
            var n = int.Parse(userInput[2], CultureInfo.InvariantCulture);
            int count = 0;
            if (y > 0.9 && x<=10.0)
            {
                while (Math.Round(x, 1 )> 1)
                {
                    x = ((x * n + 1) / (n + 1));
                    n += 1;
                    count++;
                }
                Console.WriteLine(count);
            }
            else
                Console.WriteLine("Impossible");

        }
    }
}