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