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

Example Input: Sentence: 'a man in black shirt laying on bed with a teddy bear'. Replace the letter 'd' with 'b' in the sentence.
Example Output: a man in black shirt laying on beb with a tebby bear

Example Input: Sentence: 'a plate of food which contain smothered meat, potatoes and broccoli'. Replace the letter 'p' with 'v' in the sentence.
Example Output: a vlate of food which contain smothered meat, votatoes and broccoli

Example Input: Sentence: 'a clean bathroom with a nice big bathtub'. Replace the letter 'b' with 'n' in the sentence.
Example Output:
a clean nathroom with a nice nig nathtun