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: Untied. Sentence 1: Ian remembered to keep his shoelaces tied the next time. Sentence 2: And he was dribbling the ball down the court. Sentence 3: But someone stopped on his shoelaces. Sentence 4: And Ian tripped. Sentence 5: Ian was playing basketball.
15