#include <iostream>
#include <iomanip>

#include <algorithm>
#include <string>
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed;//
	//cout << setprecision(7);//
	
	LL X,Y,L;
	cin >> X >> Y >> L;
	//上　　上進む
	//右　　右向く　右進む
	//左　　左向く　左進む
	//右上　上進む　右向く　右進む
	//左上　上進む　左向く　左進む

	//下　　右向く　下向く　下進む
	//右下　右向く　右進む　下向く　下進む
	//左下　左向く　左進む　下向く　下進む

	int ans = 0;
	if( Y < 0){
		ans += 2;
	}else{//Y >=0
		if( X != 0){
			++ans;
		}
	}
	X = abs(X);
	Y = abs(Y);
	ans += X/L;
	ans += Y/L;
	if(X%L != 0){
		++ans;
	}
	if(Y%L != 0){
		++ans;
	}
	P(ans);

	return 0;
}