Nik, if you do it without the other stuff (the REVERSE and LEADING SPACE, as set out previously) then you will be letting bad data through.
You have ALL SPACE for your INSPECT, where you need LEADING (after the REVERSE, because "trailing space" is OK but leading or embedded is no, but you can't put TRAILING on the INSPECT).
9
1
2
3
4
1
2
3
4
Only the 9 is valid, yet with your INSPECT all would be accepted.