#include <iostream>
#include <cmath> 
using namespace std;


int main(){

	int X, Y,L;
	int k = 0;

	cin >> X;
	cin >> Y;
	cin >> L;


	if ((X == 0)&&(Y == 0)) k = 0;
	if (Y > 0) k = 1;
	if ((Y > 0) && (X == 0)) k = 0;
	if (Y < 0) k = 2;
	if ((Y == 0) && (X != 0)) k = 1;

	if (abs(X%L) != 0)k++;
	if (abs(Y%L) != 0)k++;

	k = k + (abs(X / L)) + (abs(Y / L));

	cout << k << endl;

	return 0;


}