struct S {
  a: i32,
  b: i32
}

fn main()
{
  let mut p = Box::new(S {a: 5, b: 6});

  p.a = 666;
  {
    let p1 = &p;
    let p2 = &p1;

    //p1.a = 1;
    println!("P: a={} b={}", p1.a, p1.b);
    println!("P: a={} b={}", p2.a, p2.b);
  }

  p.b = 0;
  println!("P: a={} b={}", p.a, p.b)
}