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.

Title: Hacking. Sentence 1: He had his own computer and knew several programming languages. Sentence 2: Freddy was a very young very smart boy. Sentence 3: He decided to try to hack into NASA's server to find proof of aliens. Sentence 4: NASA didn't notice until Freddy had stolen a lot of data. Sentence 5: Freddy eventually got caught and never did find any evidence.
21