using System;

public class Program

{

    public static void Main()

    {

        double lenght = double.Parse(Console.ReadLine());

        double wight = double.Parse(Console.ReadLine());

        double wardrobeSide = double.Parse(Console.ReadLine());

        double hallArea = ( lenght * 100 ) * ( wight * 100 );

        double areaWardrobe = ( wardrobeSide * 100 ) * ( wardrobeSide * 100 );

        double benchArea = hallArea / 10;

        double freeSpace = hallArea - areaWardrobe - benchArea;

        double dancers = freeSpace / ( 40 + 7000 );

        Console.WriteLine("В залата има {0:F0} танцьори.", dancers );

    }

}