understanding use_count with shared_ptr

I came up with the following example

std::shared_ptr<foo> a(new foo());
{
    std::shared_ptr<foo> b = a;
    std::cout << "before" << b.use_count() << "\n"; //returns 2
    b.reset();
    std::cout << "after" << b.use_count() << "\n";  //returns 0
} 
std::cout << "Finished\n";

Now in the above code the second use_count statement returns zero. In that case isnt the destructor suppose to be called before printing out "Finished". Why is use_count in the second statement printing 0 ? I read that the definition of use_count is:

Returns the number of shared_ptr objects that share ownership over the same pointer as this object (including it).

If I did a reset() before use count that simply means that its reference count decreased by 1. Please correct me If I am wrong.

Here is my understanding of what is going on please correct me if I am wrong

std::shared_ptr<foo> a(new foo());   //reference count is 1
{
    std::shared_ptr<foo> b = a;      //reference count becomes 2
    std::cout << "before" << b.use_count() << "\n"; //returns 2 //OK this I understand
    b.reset(); //b smart pointer gives up its reference count so now it should be 1.
    std::cout << "after" << b.use_count() << "\n";  //This should be 1 why is it 0 ?
} 
std::cout << "Finished\n";

So my question is why is b.use_count() returning 0 ?