#include <iostream>
#include <sstream>
#include <math.h>
#include <stack>
#include <set>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <vector>
using namespace std;

#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int x,y,l;
	int ans = 0;
	cin >> x >> y >> l;
	ans += abs(x) / l + abs(y) / l;
	if(x % l != 0) ans++;
	if(y % l != 0) ans++;
	if(x != 0) ans++;
	if(y < 0 && x == 0) ans += 2;
	else if(y < 0) ans++;
	cout << ans << endl;
	return 0;
}