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

cmd = 0


while y != 0:
    if y > 0 and y >= l:
        cmd += 1
        y -= l
    elif y > 0 and y < l:
        cmd += 1
        y = 0
    elif y < 0 and y <= -l:
        cmd += 1
        y += l
    elif y < 0 and y > -l:
        cmd += 1
        y = 0

if x != 0:
    cmd += 1

while x != 0:
    if x > 0 and x >= l:
        cmd += 1
        x -= l
    elif x > 0 and x < l:
        cmd += 1
        x = 0
    elif x < 0 and x <= -l:
        cmd += 1
        x += l
    elif x < 0 and x > -l:
        cmd += 1
        x = 0

print(cmd)