#include <iostream>
using namespace std;

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