#include <iostream>
#include <math.h>
#include <fstream>
using namespace std;

int main()
{
	ifstream f("rubarba.in");
	ofstream g("rubarba.out");
	int *n,*q,maxx,maxy,minx,miny;
	n=new int;
	q=new int;
	f>>*n;
	f>>maxx;
	f>>maxy;
	f>>minx;
	f>>miny;
	if(maxx*maxx+maxy*maxy<minx*minx+miny*miny)
		{
			*q=maxx;
			*n=maxy;
			maxx=minx;
			maxy=miny;
			minx=*q;
			miny=*n;
		}
	while(f>>*n>>*q)
	{
		if((*n)*(*n)+(*q)*(*q)<minx*minx+miny*miny)
		{
			minx=*n;
			miny=*q;
		}
		if((*n)*(*n)+(*q)*(*q)>maxx*maxx+maxy*maxy)
		{
			maxx=*n;
			maxy=*q;
		}
	}
	float *s,*y,*x;
	f.close();
	delete q;
	delete n;
	s=new float;
	x=new float;
	y=new float;
	*y=maxy-miny;
	*x=maxx-minx;
	*s=(*y)+(*x);
	g<<((*s)*(*s)-(*x)*(*x)-(*y)*(*y))/2;
	g.close();
	delete x,y,s;
}