How do I find the last row which meets criteria??

s/s has 325501 rows.

Column C contains names of people (whether present or not -I enclose small attachment to illustrate).
Column J contains scores (if present).

I need column N to list the last row number where each column C name scored points (not just when he\she was last present).

I think I need macros which I can fill down both columns (??).
I would be most grateful for any help.
Big thanks.
Colwyn.