#include <iostream>
#include <memory>

using namespace std;

struct B {
  B(int i) : m(i) {}
  int m;
};

struct A {
  shared_ptr<B> b;
};

int
main(void)
{
  shared_ptr<B> x(new B(42));
  A* a = new A;
  A* c = new A;
  a->b = x;
  c->b = x;
  cout << x.use_count() << endl;
  delete a;
  cout << x.use_count() << endl;
  delete c;
  cout << x.use_count() << endl;

  return 0;
}