If/Then Statement writing, for blank cell to pull from another

I am trying to write a IF/THEN statement for a blank cell to pull from the one next to it. Basically if N2 is blank then pull from O2 but otherwise pull from N2.

This is what I have so far: =IF(ISBLANK(inuput!N2), input!O2, input!N2 )

Help would be appreciated :)