using System;

namespace yukicoder
{
    class Program
    {
        static void Main(string[] args)
        {
            int x = int.Parse(Console.ReadLine());
            int y = int.Parse(Console.ReadLine());
            int l = int.Parse(Console.ReadLine());
            int count = 0;
            if (y < 0)//y==-
            {
                if (x < 0)
                {
                    count++;
                    x *= -1;
                    count = Kxy(count, x, l);
                    count++;
                    y *= -1;
                    count = Kxy(count, y, l);
                }
                else
                {
                    count = Kxy(count, x, l);
                    count++;
                    y *= -1;
                    count = Kxy(count, y, l);
                }
                if (y == 0)
                {
                    Console.WriteLine(count);
                }
            }
            else//y==+
            {
                count = Kxy(count, y, l);
                if (x == 0)
                {
                    Console.WriteLine(count);
                }
                if (x < 0)//x -
                {
                    count++;
                    x *= -1;
                   count= Kxy(count, x, l);
                    Console.WriteLine(count);
                }
                else if (x > 0)
                {
                    count = Kxy(count, x, l);
                        Console.WriteLine(count);
                    
                }
            }
            static int Kxy(int count,int x,int l)
            {
                count += x / l;
                if (x % l != 0)
                {
                    count += x % l;
                }
                return count;
            }
        }
    }
}