package main

import (
	"fmt"
)

func main() {
	var X, Y, L, task int
	fmt.Scan(&X, &Y, &L)
	if X != 0 {
		task++
	}
	if X < 0 {
		X = -X
	}
	if Y < 0 {
		task += 2
		Y = -Y
	}
	if X%L > 0 {
		task += X/L + 1
	} else {
		task += X / L
	}
	if Y%L > 0 {
		task += Y/L + 1
	} else {
		task += Y / L
	}

	fmt.Println(task)
}