Try below test with empty line as a text:

--- start of input ---
world
#

--- end of input ---

Be careful, input in HEX can be presented as:
77 6F 72 6C 64 0D 0A
23 0D 0A
0D 0A

The answer is:
--- start of output ---

0
--- end of output ---

Be careful about an empty line before 0.