For an "Excellent Composition", if each page contains 600 characters, it will take 45 pages. If each page contains 900 characters, how many pages will it require? (answer with ratio)
一本《优秀作文》，如果每页排600个字，要排45页，如果每页排900个字，则要排多少页？(用比例解答)
<result>300</result>