#include<iostream>
#include<cmath>

using namespace std;

int main(){

	int X,Y,L;
	int ans=0;

	cin>>X>>Y>>L;

	ans+=(abs(X)/L)+(abs(X)%L!=0)+(abs(Y)/L)+(abs(Y)%L!=0);

	if(X==0&&Y>0) ans+=0;
	if(X==0&&Y==0) ans+=0;
	if(X==0&&Y<0) ans+=2;
	if(X>0&&Y>0) ans+=1;
	if(X>0&&Y==0) ans+=1;
	if(X>0&&Y<0) ans+=2;
	if(X<0&&Y>0) ans+=1;
	if(X<0&&Y==0) ans+=1;
	if(X<0&&Y<0) ans+=2;

	cout<<ans<<endl;
}