using System;
public class Program
{
    public static void Main()
    {
        int x = int.Parse(Console.ReadLine() ?? string.Empty);
        int y = int.Parse(Console.ReadLine() ?? string.Empty);
        int m = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] pass = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string a = Console.ReadLine() ?? string.Empty;

        int count = 0;
        if (y > 0) //北向きそのまま前進
        {
            count += y / m;
            if (y % m != 0)
            {
                count++;
            }
        }

        if (x != 0)
        {
            count++;
            if (x < 0)
            {
                x *= -1;
            }
            count += x / m;
            if (x % m != 0)
            {
                count++;
            }

        }

        if (y < 0)
        {
            if (x == 0)
            {
                count++;
            }
            count++;
            y *= -1;

            count += y / m;
            if (y % m != 0)
            {
                count++;
            }
        }

        Console.WriteLine(count);
    }
}