somuchbs

#include <iostream>
#include <cmath>
#include <math.h>
#include <iomanip>

using namespace std;
long double area(double x1, double y1, double x2, double y2, double x3, double y3)
{
    return fabs(x1 * y2 + x3 * y1 + x2 * y3 - x3 * y2 - x1 * y3 - x2 * y1);
}

int main()
{
    long double PI = 3.141592653589793;
    double x1, y1, x2, y2, x3, y3;

    while(cin>>x1>>y1>>x2>>y2>>x3>>y3)
    {
        cout<<setprecision(2)<<fixed<<hypot(x1-x2, y1-y2) * hypot(x2-x3, y2-y3) * hypot(x1-x3, y1-y3) * PI / area(x1, y1, x2, y2, x3, y3)<<endl;
    }
    return 0;
}