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

int main() {
	int x, y, l, c=0;
	cin >> x >> y >> l;
	c += abs(y/l);
	if(y%l != 0) {
		c++;
	}
	c += abs(x/l);
	if(x%l != 0) {
		c++;
	}
	if(x != 0 || (x == 0 && y < 0)) {
		c++;
	}
	if(y < 0) {
		c++;
	}
	cout << c << endl;
	return 0;
}