#include <iostream>
using namespace std;

int main() {
	long long int x, y, l,ans=0;
	cin >> x >> y >> l;
	if (y < 0) {
		if (x== 0)
			ans += 2;
		else
			ans += 1;
	}
	x = abs(x);
	y = abs(y);
	ans += y / l + (y % l != 0);
	ans += (x != 0) + x / l + (x % l != 0);
	cout << ans << "\n";
}