#include <bits/stdc++.h>
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define REP(i,k,n) for(ll i=k;i<(ll)(n);i++)
#define fore(i,a) for(auto &i:a)
using namespace std;
using ll = long long; 


int main() {
	int x,y,l;
	cin >> x >> y >> l;
	int xx = abs(x);
	int yy = abs(y);
	int ans = 0;
	if(y >= 0 && x == 0) {
		ans += (xx+l-1)/l;
		ans += (yy+l-1)/l;
	} 
	if(y >= 0 && x != 0) {
		ans++;
		ans += (xx+l-1)/l;
		ans += (yy+l-1)/l;
	} 
	if(y < 0) {
		ans += 2;
		ans += (xx+l-1)/l;
		ans += (yy+l-1)/l;
	}
	cout << ans << endl;
	return 0;
}