#include<iostream>
#include<string>
#include<cstring>
#include<complex>
#include<vector>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<iomanip>
using namespace std;

#define REP(i, j) for (int i = 0; i < (int)j; ++i)
#define FOR(i, j, k) for (int i = (int)j; i < (int)k; ++i)
#define SORT(v) sort(v.begin(), v.end())
#define REVERSE(v) reverse(v.begin(), v.end())
typedef complex<double> P;
typedef vector<int> VI;
typedef long long LL;
typedef pair<int,int> PII;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int x, y, l;
	cin >> x >> y >> l;

	LL o = 0, d = 2;
	if (y > 0) o += (y % l == 0) ? (y / l) : (y / l + 1);
	if (x != 0) {
		o += 1 + ((abs(x) % l == 0) ? (abs(x) / l) : (abs(x) / l + 1));
		d = 1;
	}
	if (y < 0) {
		y *= -1;
		o += d + ((y % l == 0) ? (y / l) : (y / l + 1));
	}

	cout << o << endl;

	return 0;
}