-- https://docs.oracle.com/en/database/oracle/oracle-database/23/lnpls/plsql-language-fundamentals.html
DECLARE
  "BEGIN" varchar2(15) := 'UPPERCASE';
  "Begin" varchar2(15) := 'Initial Capital';
  "begin" varchar2(15) := 'lowercase';
BEGIN
  DBMS_Output.Put_Line("BEGIN");
  DBMS_Output.Put_Line("Begin");
  DBMS_Output.Put_Line("begin");
END;
/