Dance hall

using System;

namespace danceHall
{
	class Program
	{
		static void Main (string[] args)
		{
			double lengthM = double.Parse(Console.ReadLine());
			double widthM = double.Parse(Console.ReadLine());
			double sideWardrobe = double.Parse(Console.ReadLine());

			double hallAreaCM = (lengthM * 100) * (widthM * 100);
			double wardrobeAreaCM = (sideWardrobe * 100) * (sideWardrobe * 100);
			double benchAreaCM = hallAreaCM / 10;

			double freeSpace = hallAreaCM - wardrobeAreaCM - benchAreaCM;
			double dancers = freeSpace / (40 + 7000);

			Console.WriteLine(Math.Round(dancers));
		}
	}
}