My sheet contains in A1:B500 lots of pairs, some of which are repeated

............A.............B
1........light........team
2........table.........cup
3........cup.........water
4.........light........team
5.........water......wine

I am interested in removing the duplicated rows (in the case above
light -- team), pushing the rest of the pairs up.

If possible, although it can complicate things, I want to sort the
pairs by column A.

Is it possible to do all this only with formulas? (I don't want to use
advanced filter)

It would help a lot.

Thank you in advance.