/* Tria shmeia, trigwno.*/
#include <iostream> 
#include <cmath>
using namespace std;
int main(int argc, char *argv[])
{ int x1,y1,x2,y2,x3,y3; 
  double area, det;
  cout<<"Dose x1,y1,x2,y2,x3,y3: ";
  cin>>x1>>y1>>x2>>y2>>x3>>y3;
  det=x1*y2+x2*y3+x3*y1-x1*y3-x2*y1-x3*y2;
  if (det==0) cout<<"Shmeia se eytheia, oxi trigwno\n";
  else {area=abs(det)/2;
       cout<<"Shmeia orizoyn trigwno me embadon "<<area<<"\n";
       }
  system("PAUSE");
  return 0; 
}