Create 3rd data set off comparison of 2 other sets
 

Hoping someone out there can help me with this. I have 2 sheets in the same
wb. I need to be able to compare the 2 sets of data in both sheets and have
them combine on a 3rd sheet. For example.
Sheet 1 has the following data in Column A:

abc
defg
hijk

Sheet 2 has the following data in Column A:

abc
hijk
lmn

I need to somehow to have sheet 3 automatically populate with all the items
that show up on both sheet 1 and sheet 2, but only show up once as in the
example below.

abc
defg
higj
lmn

The amount of data in sheets 1 and 2 will change each time the user updates
the workbook, and I need to have sheet 3 populate automatically, so I don't
know if it can be done through formulas, or if a macro is needed.

Any guidance would be appreciated.

Thanks