#include <stdio.h>
#include <stdlib.h>

int main()
{
   float x1, y1, x2, y2, x3, y3, x, y;
   float det1, det2, det3;

   printf("Point A: "); scanf("%f%f", &x1, &y1);
   printf("Point B: "); scanf("%f%f", &x2, &y2);
   printf("Point C: "); scanf("%f%f", &x3, &y3);
   printf("Point P: "); scanf("%f%f", &x, &y);

   det1 = (x2*y-x*y2) + x1*(y2-y) + y1*(x-x2);
   det2 = (x3*y-x*y3) + x2*(y3-y) + y2*(x-x3);
   det3 = (x1*y-x*y1) + x3*(y1-y) + y3*(x-x1);

   if (det1==0)
      printf("P lies on AB\n");
   else if (det2==0)
      printf("P lies on BC\n");
   else if (det3==0)
      printf("P lies on CA\n");
   else if ((det1 > 0) && (det2 > 0) && (det3 > 0))
      printf("P lies inside ABC\n");
   else if ((det1 < 0) && (det2 < 0) && (det3 < 0))
      printf("P lies inside ABC\n");
   else
      printf("P lies outside ABC\n");

   exit(0);
}