frustrating beyond belief!: trying to compare two lists of URLs

[cachaco]

so Ive tried multiple solutions from google, and every time I get the same error, Im beginning to think something is wrong with my excel (professional plus 2013)



Im trying to compare two columns of URLs so excel tells me which URLS arent repeated in both columns or which are on both columns, either way would be useful. Tried several different formulas but after I typed them always get the same error (pic below) Wasted hours and failed so I need your help, thanks