#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> Pr;

ll X, Y, L;
ll rot_num = 0;
ll go_num = 0;

int main()
{
	cin >> X >> Y >> L;
	if (X == 0) {
		if (Y != 0) {
			if (Y < 0) 
				rot_num = 2;
		}
	}
	else if (Y == 0) {
		if (X != 0) {
			rot_num = 1;
		}
	}
	else {
		if (Y > 0)rot_num = 1;
		else rot_num = 2;
	}

	if (X != 0) {
		if (L >= abs(X))
			go_num = 1;
		else {
			go_num = abs(X / L);
			if (X % L != 0)go_num++;
		}
	}
	if (Y != 0) {
		if (L >= abs(Y))
			go_num += 1;
		else {
			go_num += abs(Y / L);
			if (Y % L != 0)go_num++;
		}
	}
	cout << go_num + rot_num << endl;
	return	0;
}