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

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

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

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

	return 0;
}