def f(n, l):
    abs_n = abs(n)
    abs_l = abs(l)
    if abs_n % abs_l == 0:
        return abs_n // abs_l
    else:
        return (abs_n // abs_l)+1
def g(x, y):
    if y < 0:
        return 2
    elif x == 0:
        return 0
    else:
      return 1

X = int(input())
Y = int(input())
L = int(input())
print(f(X, L) + f(Y, L)+ g(X, Y))