--- a/hgext3rd/topic/stack.py	Mon Sep 03 16:41:32 2018 +0200
+++ b/hgext3rd/topic/stack.py	Mon Sep 03 17:07:36 2018 +0200
@@ -239,11 +239,11 @@
         msg %= (branch, topic)
         raise error.ProgrammingError(msg)
     elif topic is not None:
-        prefix = 't'
+        prefix = 's'
         if topic not in repo.topics:
             raise error.Abort(_('cannot resolve "%s": no such topic found') % topic)
     elif branch is not None:
-        prefix = 'b'
+        prefix = 's'
     else:
         raise error.ProgrammingError('neither branch and topic specified (not defined yet)')