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

procedure Main is
	s:Integer;
    w:Integer;
begin
	get(s);
	get(w);
	if w>=s then
		Put_Line("unsafe");
	else
		Put_Line("safe");
	end if;
      
end Main;
