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

if(X > 0):
	while x < X:
		count += 1 
		x += L
elif(X < 0):
	while x > X:
		count +=1 
		x -= L 
else:
	pass

if(Y > 0):
	while y < Y:
		count += 1 
		y += L
elif(Y < 0):
	while y > Y:
		count +=1 
		y -= L 
else:
	pass

if ((Y < 0)and(X <= 0)):
	count += 2
elif((Y >= 0)and(X < 0)):
	count += 1
elif(X > 0):
  count += 3
else:
	pass

print(count)