begin
   comment LIBRARY 1;
   integer
     I;
   switch S ≔      S1,
     S2,
     S3,
     S4;
   for I ≔ 1 step 1 until 4 do
      begin
         goto S[I];
         S1 :;
         if I ≠ 1 then
           OUTREAL(99, I)
         else
           goto EXIT;
         S2 :;
         if I ≠ 2 then
           OUTREAL(99, I)
         else
           goto EXIT;
         S3 :;
         if I ≠ 3 then
           OUTREAL(99, I)
         else
           goto EXIT;
         S4 :;
         if I ≠ 4 then
           OUTREAL(99, I)
         else
           goto EXIT;
         EXIT :;
      end;
end