using System;
using System.Linq;

public class yukicoder{
    
    public static double walk(double goal, double n)
    {
        double x = Math.Abs(goal);
        return Math.Ceiling(x / n);
    }
    
    public static double turn(double NS, double EW)
    {
		double command = 0;
		
		if(NS < 0)
		{
			command = command + 2;
		}
		if(EW != 0)
		{
			command++;
		}
		
		return command;
    }
    
    public static void Main(){
        double EW = double.Parse(Console.ReadLine());
        double NS = double.Parse(Console.ReadLine());
        double forward = double.Parse(Console.ReadLine());
        
        Console.WriteLine(turn(NS, EW) + walk(NS, forward) + walk(EW, forward));
    }
}