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

Example Input: Sentence: 'a woman gives a thumbs up sign while sitting in front of a sandwich'. Replace the letter 's' with 'h' in the sentence.
Example Output: a woman giveh a thumbh up hign while hitting in front of a handwich

Example Input: Sentence: 'this refrigerator is covered in stickers on it'. Replace the letter 't' with 'h' in the sentence.
Example Output: hhis refrigerahor is covered in shickers on ih

Example Input: Sentence: 'a giraffe stands next a brick wall and a door'. Replace the letter 'g' with 'u' in the sentence.
Example Output:
a uiraffe stands next a brick wall and a door