What does `Rc::strong_count` print at the marked line?
use std::rc::Rc;
use std::cell::RefCell;
fn main() {
let a = Rc::new(RefCell::new(5));
let b = Rc::clone(&a);
{
let c = Rc::clone(&b);
let _w = Rc::downgrade(&a);
}
println!("{}", Rc::strong_count(&a)); // marked line
}