In this task, you're given the title of a story consisting of five sentences, numbered 1 through 5. Your job is to determine which two sentences need to be swapped sentences in order to make a story that makes complete sense and is befittingly titled. Indicate your answer using the numbers of the two sentences in order, such as '34' or '25'. The first digit refers to the sentence which should come first in the story.
Q: Title: Alan's Paper. Sentence 1: Alan had to write a paper for class. Sentence 2: Alan turned in his paper to be graded. Sentence 3: Alan checked out a few books. Sentence 4: He read through the books and wrote his paper. Sentence 5: He went to the library to do research.
A: 
25