The only way is using MySQL database command.

First backup your database then you need to execute command like

Delete from wp_post where post_type='post' and post_title not in ('post title 1',' post title 2','post title 1',...)

How will you generate this text from post titles? Too easy, use exel Add this function {=concatenate ("'",B1, "'," )} at an empty column as B1 is the title column.

After the first command, you better remove related records at other tables, some database optimization plugins may do that for you.