Emma has a small bookshelf with space for 6 books in a row. She has 4 fiction books (each marked with an F) and 2 non-fiction books (each marked with an N). Emma wants to arrange these books on the shelf.

How many different ways can Emma arrange the 6 books on the shelf?

Note: Switching two fiction books doesn’t count as a new arrangement, since all the fiction books look the same. The same applies to the non-fiction books.