#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
class trikampis
{
  private:
      int x1, y1, x2, y2, x3, y3;
      double S;
  public:
      trikampis():x1(0),y1(0),x2(0),y2(0), x3(0), y3(0){}
      trikampis(int a, int b, int c, int d, int e, int f):x1(a),y1(b),x2(c),y2(d),x3(e),y3(f){};
      ~trikampis(){}
  void ived()
  {
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
  }
  double plotas()
  {
    double a, b, c, p;
    a =sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
    b =sqrt((x2-x3)*(x2-x3)+(y2-y3)*(y2-y3));
    c =sqrt((x3-x1)*(x3-x1)+(y3-y1)*(y3-y1));
    p = (a+b+c)/2.;
    S = sqrt(p*(p-a)*(p-b)*(p-c));

  }
  double graz_plotas()
  {
    return S;
  }


};

int main()
{
  int n;
  double plot;
  int min = 0;
  cin >> n;
  trikampis *T = new trikampis [n];
  for (int i = 0; i < n; i++) {
    T[i].ived();
    plot = T[i].plotas(); }

  if (plot == 0) cout << "NO";
  else if (plot != 0 && plot < min)
  cout << fixed << setprecision(2) << min;


}