#include<iostream>

using namespace std;

int main(){
	int x,y,l;
	cin>>x>>y>>l;
	int cnt=0;

	if(x)cnt=1;
	if(x<0)x*=-1;
	if(y<0){
		cnt=2;
		y*=-1;
	}
	cnt+=(y+l-1)/l;
	cnt+=(x+l-1)/l;
	cout<<cnt<<endl;
}