x = int(input())
y = int(input())
d = int(input())

y1, y2 = divmod(y, d)
x1, x2 = divmod(x, d)

if y > 0 and y1 < 0:
    y1 = 0
if x > 0 and x1 < 0:
    x1 = 0

if y2 != 0:
    y2 = 1
if x2 != 0:
    x2 = 1

z = abs(y1) + y2 + abs(x1) + x2

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

print(z)