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

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: 'a couple sits on a bench in the countryside'. Replace the letter 'y' with 'k' in the sentence.
Example Output: a couple sits on a bench in the countrkside

Example Input: Sentence: 'a large amount of fruit set on a counter near a computer'. Replace the letter 'p' with 'l' in the sentence.
Example Output:
a large amount of fruit set on a counter near a comluter