Oracle SQL/PL Using VSIZE in a Procedure

I am trying to output to the command line screen the nr of bytes (using VSIZE) in the string 'nOT', 'easy'. The first code snippet works fine, setting the first character of each string in capitals.

However I cannot display the number of bytes using VSIZE. Any ideas? Been scratching my head and trying/failing for over an hour now :mad:

Thanks.

First snippet: (Works fine)

CREATE OR REPLACE PROCEDURE pleasehelp (firstname IN NVARCHAR2, surname IN NVARCHAR2)
IS
 BEGIN 
             DBMS_OUTPUT.PUT_LINE (INITCAP (firstname)  || INITCAP (surname)); 
                      
           
END pleasehelp;
/ 

set serveroutput on;
BEGIN 
   pleasehelp (‘nOT’, ‘easy’);
  
END; 	
/

Second code snippet (attempting to using VSIZE to output number of bytes)

CREATE OR REPLACE PROCEDURE pleasehelp (firstname IN NVARCHAR2, surname IN NVARCHAR2)
IS
 BEGIN 
             DBMS_OUTPUT.PUT_LINE (INITCAP (firstname)  || INITCAP (surname)); 
             DBMS_OUTPUT.PUT_LINE (VSIZE(firstname) || VSIZE(surname));          
           
END pleasehelp;
/ 

set serveroutput on;
BEGIN 
   pleasehelp (‘nOT’, ‘easy’);
  
END; 	
/