using static System.Math;
using System;

public class Hello
{
    public static void Main()
    {
        var x = int.Parse(Console.ReadLine().Trim());
        var y = int.Parse(Console.ReadLine().Trim());
        var L = int.Parse(Console.ReadLine().Trim());
        Console.WriteLine(getAns(x,y,L));
    }
    public static int getAns(int x, int y, int a)
    {
        var ans = (Abs(x) + a - 1) / a + (Abs(y) + a - 1) / a;
        if (x == 0 && y >= 0) return ans;
        if (y < 0) ans += 2;
        else ans++;
        return ans;
    }
}