import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

from math import ceil

x = int(readline())
y = int(readline())
l = int(readline())
cnt = 0
if x != 0:
    x = abs(x)
    cnt += 1
if y < 0:
    y = abs(y)
    cnt += 1
    if x == 0:
        cnt += 1
print(ceil(y / l) + ceil(x / l) + cnt)