package Q is

    procedure Read(S : out Integer);
    procedure Restore(S : in out Integer);

end Q;
package P is

    type Int_Ptr is access all Integer;
    procedure Exec(P : Int_Ptr);

end P;
with Q; use Q;

package body P is

    procedure Lock is
        S : Integer;
    begin
        Read(S);
        Restore(S);
    exception
        when others => Restore(S);
    end;

    procedure Exec(P : Int_Ptr) is
    begin
        while P /= NULL loop
            Lock;
        end loop;
    end;

end P;