def calc(a, l):
    a, l = map(abs, divmod(a, l))
    return a + l


def some():
    x, y, l = [int(input()) for i in range(3)]
    keisuu = 1
    ans = 0
    if x == 0 or y == 0:
        keisuu = 0
    ans += calc(x, l)
    ans += calc(y, l)
    # quo, remain = divmod(x, l)
    # ans += quo + remain
    # quo, remain = divmod(y, l)
    # ans += quo + remain
    ans += keisuu
    print(ans)

some()