package main

import (
	"fmt"
	"math"
)

func scan() (X int, Y int, L int) {
	fmt.Scan(&X, &Y, &L)
	return
}

func main() {
	var X, Y, L int
	X, Y, L = scan()
	// X, Y, L = 0, 2, 1
	// X, Y, L = -7, 15, 7
	count := 0
	if X == 0 {
		count += 0
	} else if Y >= 0 {
		count += 1
	} else if X < 0 && Y < 0 {
		count += 2
	}

	if X != 0 {
		count += (int(math.Abs(float64(X))) + L - 1) / L
	}
	if Y != 0 {
		count += (int(math.Abs(float64(Y))) + L - 1) / L
	}
	fmt.Print(count)
}