#include <iostream>
#include <algorithm>
#include <vector>
#include<string>

using namespace std;
int main() {
	int x, y, l;
	int x_ori;
	int count = 0;
	cin >> x >> y >> l;

	if (x < 0 ) {
		count++;
		x_ori = abs(x);
	} else {
		x_ori = x;
	}
	count += (x_ori / l);
	if (x_ori%l != 0) count++;
	//cout << count << "\n";

	if (y < 0) {
		if (x >= 0) {
			count += 2;
		} else {
			count++;
		}
		y = abs(y);
	}
	count += (y / l);
	if (y%l != 0) count++;
	cout << count << endl;

	return 0;
}