TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a young baseball player throws the ball as others watch'. Replace the letter 'a' with 'n' in the sentence.

SOLUTION: n young bnsebnll plnyer throws the bnll ns others wntch

PROBLEM: Sentence: 'a person is riding a motorcycle as part of some kind of performance'. Replace the letter 'm' with 'a' in the sentence.

SOLUTION: a person is riding a aotorcycle as part of soae kind of perforaance

PROBLEM: Sentence: 'a bunch of people are standing around with umbrellas'. Replace the letter 'u' with 'n' in the sentence.

SOLUTION:
a bnnch of people are standing aronnd with nmbrellas