X = int(input())
Y = int(input())
L = int(input())
count = 0

if X < 0:
    x = X * (-1)
else:
    x = X
if Y < 0:
    y = Y * (-1)
else:
    y = Y

if x > L:
    count_x = x // L
    if x % L > 0:
        count_x += 1
elif x == 0:
    count_x = 0
else:
    count_x = 1

if y > L:
    count_y = y // L
    if y % L > 0:
        count_y += 1
elif y == 0:
    count_y = 0
else:
    count_y = 1

if X == 0:
    if Y >= 0:
        count = 0
    elif Y < 0:
        count = 2
elif X != 0:
    if Y >= 0:
        count = 1
    elif Y < 0:
        count = 2
print(count + count_x + count_y)