with Ada.Text_IO;
with Ada.Integer_Text_IO;
with Ada.Float_Text_IO;
use Ada.Text_IO;
use Ada.Integer_Text_IO;
use Ada.Float_Text_IO;

procedure hoge is
 a: integer;
 b: integer;
begin
 get(a);
 get(b);
 if a>=10 then
  put(-1);
 elsif b>=10 then
  put(-1);
 else
  put(a*b);
 end if;
end hoge;