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

procedure Solve is
   S : Integer;
   W : Integer;
begin
   Get (S);
   Get (W);
   if W >= S then
      Put_Line ("unsafe");
   else
      Put_Line ("safe");
   end if;
end Solve;