class Program
{
    static void Main(string[] args)
    {
        string inputX = Console.ReadLine()!;
        string inputY = Console.ReadLine()!;
        string inputRange = Console.ReadLine()!;

        int x = int.Parse(inputX);
        int y = int.Parse(inputY);
        int range = int.Parse(inputRange);
        int count = 0;

        if (x <= -1)
        {
            x = Math.Abs(x);
        }
        if (y <= -1)
        {
            count++;
            y =  Math.Abs(y);
        }

        int xCount = x / range;
        if (xCount * range < x)
        {
            xCount++;
        }

        int yCount = y / range;
        if (yCount * range < y)
        {
            yCount++;
        }

        if(x != 0)
        {
            count++;
        }

        count += xCount + yCount;

        Console.WriteLine(count);

    }
}