cannot strip

[Uwe Brauer]

Hi

I wanted to strip all changesets of a new branch in draft mode.

The part of the graph looks like


â—‹  changeset:   2477:7a28356c5f3e
│  Branch:      2021-22
│  Author:      Uwe Brauer <oub at mat.ucm.es>
│  Date:        Fri, 08 Oct 2021 17:18:40 +0200
│  Topic:       examen-extra
│  Phase:       draft
│  Summary:     Add the first virtual comment
│
â—‹  changeset:   2476:befd7579cbcc
│  Branch:      default
│  Author:      Uwe Brauer <oub at mat.ucm.es>
│  Date:        Fri, 08 Oct 2021 17:14:36 +0200
│  Topic:       examen-extra
│  Phase:       draft
│  Summary:     Finish the year


But hg strip -r 2477 gives

abort: unknown revision '2021-22'!


What the hell is up here?