Definition: In this task, you're given five sentences, numbered 1 through 5, and two options a and b for possible titles for the story. Your job is to choose the title that better fits the story. Indicate your choice by 'a' or 'b'.
Input: Sentence 1: Rina went to Russia on a student exchange program. Sentence 2: She was nervous at first - Russia was so foreign. Sentence 3: But soon she was very comfortable there. Sentence 4: She even learned to speak fluent Russian! Sentence 5: At the end of the semester, she hated to leave. Choices: a. Overdraft. b. Exchange.

b