#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;


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

	long long ans = 0;
	ans += abs(x)/l + (abs(x)%l==0?0:1);
	ans += abs(y)/l + (abs(y)%l==0?0:1);

	if(y<0) ans += 2;
	else if(x!=0) ans += 1;

	cout << ans << endl;
	return 0;
}