class A
{ 
public:
  int a;
  virtual ~A() {}
};

class B : public A
{ 
public:
  int b;
};


class C : public B
{ 
public:
  int c;
};

int f(const A* aptr)
{

  if (const B* bptr =
      dynamic_cast<const B *>(aptr))
    {
      return 0;
    }
  else
  {
    return 1;
  }

    
}

int main()
{

  C c;

  return f(&c);

}