def ceildiv(a: int, b: int) -> int:
    return (a + b - 1) // b


X = int(input())
Y = int(input())
L = int(input())


def f():
    dx = ceildiv(abs(X), L)
    dy = ceildiv(abs(Y), L)

    if Y < 0:
        return dx + dy + 2
    if X != 0:
        return dx + dy + 1
    return dx + dy


ans = f()
print(ans)