Uses MyCrt;
Var
  Timer : LongInt Absolute {Seg0040}$40:$6C;
  o : LongInt;
  c : Char;

BEGIN
  c:=#0;
  o:=Timer;
  Repeat
    If o<>Timer then
    Begin
      o:=Timer;
      write(#13,o shr 4);
    End;
    if keypressed then c:=readkey;
  Until c=#27;
END.