Problem D

USING: io kernel math math.parser strings sequences locals ;

IN: template

:: test ( rtn cur -- a b )

  cur "" =
  [ rtn cur ]
  [
    cur 1 tail
    cur 1 head


    dup "1" = [ drop "" ] [ ] if
    dup "2" = [ drop "" ] [ ] if
    dup "3" = [ drop "" ] [ ] if
    dup "4" = [ drop "" ] [ ] if
    dup "5" = [ drop "" ] [ ] if
    dup "6" = [ drop "" ] [ ] if
    dup "7" = [ drop "" ] [ ] if
    dup "8" = [ drop "" ] [ ] if
    dup "9" = [ drop "" ] [ ] if
    dup "0" = [ drop "" ] [ ] if

    rtn
    swap
    append
    swap
    test

  ]
  if ;





""
readln
test

drop
print