comment CHECK ON NONTERMINATING FOR LOOPS IN OPT MODE;
begin integerI
     ;for I ≔ 1 step 1 until 3 do PRINT(I,3,0);
   NEWLINE;
   for I ≔ 1 step 2 until 5 do PRINT (I,3,0);
   NEWLINE;
   PRINT(I,3,0)
end