#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) (x > 0) ? x : x * -1

int main() {
	long long int x, y, l, ans = 0;
	cin >> x >> y >> l;

	if (y < 0)			ans += 2;
	else if (x != 0)	ans++;

	x = us(x);
	y = us(y);

	ans += y / l;
	ans += x / l;
	if (x % l != 0)	ans++;
	if (y % l != 0) ans++;
	cout << ans << endl;

	return 0;
}