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

int main() {
	int x, y, l;
	cin >> x >> y >> l;
	
	int cntx = (abs(x) + l - 1) / l;
	int cnty = (abs(y) + l - 1) / l;
	int rot;
	
	if (y > 0) {
		if (x == 0) rot = 0;
		else rot = 1;
	}
	else if (y == 0) {
		if (x == 0) rot = 0;
		else rot = 1;
	}
	else {
		rot = 2;
	}
	
	cout << cntx + cnty + rot << endl;
	return 0;
}