#include<bits/stdc++.h>
using namespace std;

int main(){
	cin.tie(0),ios::sync_with_stdio(false);
	int x,y,l; cin>>x>>y>>l;
	int ans=(abs(x)+abs(y)+l-1)/l;
	if(y<0)ans+=2;
	else if(x)++ans;
	cout<<ans<<"\n"s;
}