import math
x = int(input())
y = int(input())
l = int(input())

xmove = math.ceil(abs(x) / l)
ymove = math.ceil(abs(y) / l)

turn = 0
turn = turn + 1 if x != 0 else turn
turn = turn + 1 if y < 0 else turn
turn = turn + 1 if y < 0 and x == 0 else turn

print(xmove + ymove + turn)