# -*- coding: utf-8 -*-
x = int(input())
y = int(input())
l = int(input())

rotation = 0
if x != 0 and y > 0:
    rotation = 1
elif x == 0 and y > 0:
    rotation = 0
elif x != 0 and y == 0:
    rotation = 1
elif x == 0 and y == 0:
    rotation = 0
elif x != 0 and y < 0:
    rotation = 2
elif x == 0 and y < 0:
    rotation = 2

x_num = 0
y_num = 0

x = abs(x)
y = abs(y)

if x % l == 0:
    x_num = int(x / l)
else:
    x_num = x // l + 1
if y % l == 0:
    y_num = int(y / l)
else:
    y_num = y // l + 1

print(x_num + y_num + rotation)