if A2 = B2 then add 'Y' in C2 ... ?

I'm trying to figure out a formula to rule-out errors/typos by comparing two columns that should have identical contents. This is my idea:
if A2 = B2 then add 'Y' in C2 ... then I'll filter or sort on Column C. The rows without a 'Y' will be the ones with the typos.
Any ideas on a formula would be very much appreciated.
much thanks!