rail, 175 bytes

Result

WA

Code [DL]

$ 'main' (--):
 \
  \-[hello ](!h!)-[world\n\](!w!)-\
                                  |
   /------------------------------/
   |
   \
  /--&-(w)o-#
  |
  \-(!l!)-(h)o-(l){}#

stdin

1728826934748639227919168334614196599335029701509019453495849308927902204432472752962005779623419513

stdout

hello world

stderr

strace