Hello I need some Help. I have looked around and have found somewhat similar
answers to what I need but can't quite get what I want. It is fairly simple.
I have 2 columns with project numbers. They look as so

18212 18212
18331 18212
18340 18331
18374 18340
18410 18374
18420 18427 <--- Note the missing 18410 + 18420
18427 18427
18478 18427
18484 18427

Basically one is longer than the other and I need to make these columns
identical without loosing any of the data. I want to insert a cell where the
two are different and copy the proj number into it. Most of the work will be
done on the left column to match the right BUT THERE ARE SOME IN THE LEFT
THAT DONT EXISIT IN THE RIGHT. If cells are already matched then skip and
check the next 2.

PLEASE HELP (Nobody has answered any of my other posts)
Thanks, Jeff.