Function s in PL/SQL

set serveroutput on;
set verify off;
declare
a int;
c int;
b int;

function pied(x in  number)
return number
is
v number(2);
begin
c:=x+10;
return(c);

end pied;


begin
a:=&a;
 b:=pied(a);
dbms_output.put_line(b);
end;