x = int(input())
y = int(input())
l = int(input())
walk_h = 0
walk_w = 0
rotate = 0

if x == 0:
  walk_w = 0
elif abs(x) <= l:
  walk_w = 1
else:
  walk_w = abs(x) // l + abs(x) % l

if y == 0:
  walk_h = 0
elif abs(y) <= l:
  walk_h = 1
else:
  walk_h = abs(y) // l + abs(y) % l

if not x < 0:
  rotate += 1
elif x == 0 and y < 0:
  rotate += 2
elif x < 0 and y < 0:
  rotate += 2

print(walk_w + walk_h + rotate)