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

Example Input: Sentence: 'a mobile phone and a set of keys on a key chain'. Replace the letter 's' with 'j' in the sentence.
Example Output: a mobile phone and a jet of keyj on a key chain

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 street sign outside a department store glass window display'. Replace the letter 'n' with 'p' in the sentence.
Example Output:
a street sigp outside a departmept store glass wipdow display