package main

import (
	"fmt"
	"math"
)

func main() {
	var X, Y, L int
	fmt.Scan(&X, &Y, &L)

	absX := int(math.Abs(float64(X)))
	absY := int(math.Abs(float64(Y)))

	var ans int

	if Y >= 0 && X == 0 {
		ans = Y / L + X / L
	} else if Y >= 0 && absX > 0 {
		ans = Y / L + absX / L + 1
	} else if Y < 0 && absX > 0 {
		ans = absY / L + absX / L + 2
	}

	fmt.Println(ans)
}