xzahyo = int(input());
yzahyo = int(input());
kyori =  int(input());
counter = 0;

if yzahyo ==0:
	if xzahyo > 0:
		counter = counter + int(xzahyo/kyori);
		if xzahyo%kyori > 0:
			counter = counter + 1;
	elif xzahyo < 0:
		counter = counter + int(-xzahyo/kyori);
		if (-xzahyo)%kyori > 0:
			counter = counter + 1;

elif yzahyo < 0:
	
	
	if xzahyo > 0:
		counter = counter + int(xzahyo/kyori)+1;
		if xzahyo%kyori > 0:
			counter = counter + 1;
	elif xzahyo < 0:
		counter = counter + int(-xzahyo/kyori)+1;
		if (-xzahyo)%kyori > 0:
			counter = counter + 1;

	counter = counter + int(-yzahyo/kyori)+1;
	if (-yzahyo)%kyori > 0:
		counter = counter + 1;

elif yzahyo > 0:
	counter = counter + int(yzahyo/kyori);
	if yzahyo%kyori > 0:
		counter = counter + 1;
	
	if xzahyo > 0:
		counter = counter + int(xzahyo/kyori)+1;
		if xzahyo%kyori > 0:
			counter = counter + 1;
	elif xzahyo < 0:
		counter = counter + int(-xzahyo/kyori)+1;
		if (-xzahyo)%kyori > 0:
			counter = counter + 1;

print(counter);