Revert "Change the output message from 'Hello' to 'Hello World'."

This reverts commit f562cb8b28a8fabee2b2be4820ded06befabefea.
Revert "Revert "Change the output message from 'Hello' to 'Hello World'.""

This reverts commit 53fb8ee7602f52960edc84d1255c8c310fee41be.