#include <bits/stdc++.h>
using namespace std;
using LL=long long;
int main()
{
	LL X, Y, L;
	cin >> X >> Y >> L;

	cout << ( abs( X ) + L - 1 ) / L + ( abs ( Y ) + L - 1 ) / L
		+ ( Y < 0 ? 2 : X != 0 ? 1 : 0 ) << endl;

	return 0;
}