package main

import (
	"fmt"
	"math"
)

func main() {
	var x, y, l float64
	_, _ = fmt.Scan(&x, &y, &l)

	mx := math.Ceil(math.Abs(x) / l)
	if mx > 0 {
		mx += 1
	}
	fmt.Println(mx + math.Ceil(math.Abs(y)/l))
}