class Problem0048:
	def solve(this):
		x = int(input())
		y = int(input())
		l = int(input())
		
		res = 0
		if x != 0:
			res += 1
		if y < 0:
			res += 2
		
		x = abs(x)
		y = abs(y)
		
		ax = x // l
		if x % l != 0:
			ax += 1
		ay = y // l
		if y % l != 0:
			ay += 1
		res += ax + ay
		print(res)

if __name__ == "__main__":
	problem = Problem0048()
	problem.solve()