In this task, you need to replace a letter in the sentence with another given letter.

Example Input: Sentence: 'two children struggle over a bat in their playroom'. Replace the letter 't' with 'v' in the sentence.
Example Output: vwo children svruggle over a bav in vheir playroom

Example Input: Sentence: 'a close up of a train on train tracks at night'. Replace the letter 'n' with 'm' in the sentence.
Example Output: a close up of a traim om traim tracks at might

Example Input: Sentence: 'people are standing at an inflatable desk over a fire hydrant'. Replace the letter 'a' with 'n' in the sentence.
Example Output:
people nre stnnding nt nn inflntnble desk over n fire hydrnnt