using System;

namespace ConsoleApplication1
{
    internal class Class1
    {
        public static void Main(string[] args)
        {

                       double L = double.Parse(Console.ReadLine());
                       double W = double.Parse(Console.ReadLine());
                       double A = double.Parse(Console.ReadLine());

                       double zala = L * 100 * W * 100;
                       double garderob = A *100* A*100;
                       double pejka = zala / 10;
                       double tanci = zala - garderob - pejka;
                       double tanciori = tanci / (40 + 7000);

                       Console.WriteLine(Math.Floor(tanciori));
        }
    }

}