#include "bits/stdc++.h"
using namespace std;
using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<ll, ll> P;
#define rep(i,n) for (ll i = 0; i < (n); ++i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const long long mod = 1e9 + 7;

ll gcd(ll a, ll b) {
	return b ? gcd(b, a % b) : a;
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

int main() {
	ll x, y, l;
	cin >> x >> y >> l;

	ll turn=0;
	ll move=0;

	if (y > 0) {
		move += (y+l-1)/l;
	} else if (y < 0) {
		turn = 2;
		move += (abs(y) + l - 1) / l;
	}

	if (x != 0) {
		turn=1;
		move += (abs(x) + l - 1) / l;
	}

	ll ans = move + turn;

	cout << ans << endl;
}