PROCEDURE SHELL(N,T:INTEGER;F:LL;VAR L:LL);
    VAR I,J,S,H,KEY:INTEGER;
    BEGIN
      FOR S:=T DOWNTO 1 DO
        BEGIN
          H:=F[S];
          FOR J:=H+1 TO N DO
            BEGIN
              KEY:=L[J];
              I:=J-H;
              WHILE (I > 0) AND (L[I] > KEY) DO
                BEGIN
                  L[I+H]:=L[I];
                  I:=I-H
                END;
              L[I+H]:=KEY
            END
        END
    END;