x = int(input())
y = int(input())
l = int(input())
order_counter = 0
move_counter = 0
rotation_counter = 0

# for rotation_counter  
if y != 0:
    if y < 0:
        rotation_counter += 1
if x != 0:
    rotation_counter += 1

# for move_counter
xy_list = [x,y]
for i in xy_list:
    q,mod = divmod(abs(i),l)
    if mod == 0:
        move_counter += q
    else:
        move_counter += q+1


order_counter = rotation_counter + move_counter        
print(order_counter)