EastWest, NorthSouth, Length = [int(input()) for _ in range(3)]
i = 0

if EastWest != 0 and NorthSouth >= 0:
    i += 1
if EastWest <= 0 and NorthSouth < 0:
    i += 2

EastWest = abs(EastWest)
NorthSouth = abs(NorthSouth)

i += EastWest // Length + NorthSouth // Length

if EastWest % Length != 0:
    i += 1
if NorthSouth % Length !=0:
    i += 1

print(i)