Hello Escuan,
Which letters do you have? There is only one solution for N and this should lead you to the only solution for 8ac.
n is one of two possibilities, in this case the lower of the two, which should lead you to only two possibilities for R and r (both possible to start with but after a couple of checks you should see which one is r and which one is R).
That should lead you to solving T and t next, then m, then u.