#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 || y == 0) {
		x = abs(x);
		y = abs(y);
		count += (x + y) / l;
		if ((x + y) % l != 0)count++;
	}else{
		if (x < 0) count++;
		if (y < 0) count++;
		if (0 < x && 0 < y)count++;
		x = abs(x);
		y = abs(y);

		count += (x / l);
		if (x%l != 0)count++;

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