//inlclude前用define 
#define _USE_MATH_DEFINES

//include
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>

using namespace std;
//typedef
typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<char> VC;

int main() {
	int x, y, l; 
	cin >> x >> y >> l;
	int cnt = 0;
	if (y >= 0) {
		if (y%l == 0) cnt += y / l;
		else cnt += (y + l) / l;

		if (x != 0) {
			cnt++; x = abs(x);
			if (x%l == 0) cnt += x / l;
			else cnt += (x + l) / l;
		}
	} else {
		if (y < 0 && x!=0) cnt++;
		y = abs(y);
		x = abs(x);
		if (x != 0) cnt++;
		else if(y!=0) cnt += 2;

		if (y%l == 0)cnt += y / l;
		else cnt += (y + l) / l;
		
		if (x%l == 0)cnt += x / l;
		else cnt += (x + l) / l;
	}
	cout << cnt << endl;
	return 0;
}