x = int(input())
y = int(input())
l = int(input())

def count(num1,num2):
    if num1%num2 == 0:
        return int(num1/num2)
    else :
        return int(num1/num2) + 1

if x == 0 or y == 0:
    print(0 + count(abs(x),l) + count(abs(y),l))
else :
    print(1 + count(abs(x),l) + count(abs(y),l))