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

Example Input: Sentence: 'a piece of chocolate cake is on a plate with a fork'. Replace the letter 'e' with 's' in the sentence.
Example Output: a piscs of chocolats caks is on a plats with a fork

Example Input: Sentence: 'a giraffe standing alone with a low fence behind it'. Replace the letter 't' with 'o' in the sentence.
Example Output: a giraffe soanding alone wioh a low fence behind io

Example Input: Sentence: 'a man riding a motorcycle on it's front tire'. Replace the letter 't' with 'm' in the sentence.
Example Output:
a man riding a momorcycle on im's fronm mire