using System;
using System.Linq;

class Picnic
    {
        //Students from 5th class decided to make a picnic. Each class had to buy something.
        //And Teddy is dropped to provide soft drink. However,
        //it is difficult for how to buy bottles of soda for all students,
        //if every child drink - 2 cups of 200 ml.
        //Write a program piknik, which calculates how many bottles to buy Teddy

        //Input
        //From the standard input is read three integers k, l and ml. k – number of students,
        //l and lm – capacity of one bottle of soft drink.
        //Exit
        //The standard output displays one number - the number of bottles of soda that Teddy will buy.

        static void Main(string[] args)
        {

            int k = int.Parse(Console.ReadLine());
            int l = int.Parse(Console.ReadLine());
            int ml = int.Parse(Console.ReadLine());


            if(k < 1 || k > 26 || l > 20 || l < 0 || ml < 0 || ml > 1000){
                return;
            }

            double val =  Convert.ToDouble(ml) / 1000;
            val += Convert.ToDouble(l);

            double answer = 0;
            answer = (Convert.ToDouble(k) * 0.4) / val;

            if (answer != Math.Round(answer))
            {
                answer = Math.Floor(answer) + 1;
            }

            Console.WriteLine(Convert.ToInt32(answer));

        }
    }