1.00 1.00 3.00 3.00 2.00 2.00 4.00 4.00
5.00 5.00 13.00 13.00 4.00 4.00 12.50 12.50

1.00
56.25

#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <cmath>
using namespace std;

int main()
{
	double x[4], y[4], x1, x2, y1, y2, s;
	while (cin >> x[0]>> y[0]>>x[1]>>y[1]>>x[2]>>y[2]>>x[3]>>y[3])
	{
		x1 = fabs(x[1] - x[0]);
		x2 = fabs(x[3] - x[2]);
		y1 = fabs(y[1] - y[0]);
		y2 = fabs(y[3] - y[2]);
		sort(x,x+4);
		sort(y,y+4);
		if ( (x[3]-x[0]) < x1+x2  &&  (y[3]-y[0]) < y1+y2)
		{
			s = ( x[2] -x[1]) * (y[2] - y[1]);
			printf("%.2lf\n",s);
		}
		else
			cout << "0.00"<< endl;
	}
	return 0;
}