In C: How to calculate the the number of pointers storing the address of variable?

main()
{
  int a;
  int *p1 , * p2 , *p3;
  p1 = &a;
  p2 = p1;
  p3 = p2;
}

What do i get the output as 3. Since there are 3 pointers holding the value of the variable 'a'.