Pl/SQL program to find square of a user input number Using Function

declare
  value1 number;
  value2 number;
  mytotal number;
  function myfun(myval1 in number, myval2 in number) return number is
    total number;
  begin
    total := myval1 ** myval2;
    dbms_output.put_line(total);
    return total;
  end;
begin
  value1 :=&val1;
  value2 := &val2;
 mytotal:= myfun(value1, value2);
end;