You will be given a definition of a task first, then some input of the task.
In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a tennis player bends over to retrieve a tennis ball'. Replace the letter 'n' with 'a' in the sentence.
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
a teaais player beads over to retrieve a teaais ball