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

Example Input: Sentence: 'a group of people riding on top of snow boarding equipment'. Replace the letter 'e' with 'x' in the sentence.
Example Output: a group of pxoplx riding on top of snow boarding xquipmxnt

Example Input: Sentence: 'there is a young baby that is wearing a tie'. Replace the letter 't' with 'c' in the sentence.
Example Output: chere is a young baby chac is wearing a cie

Example Input: Sentence: 'a stop sign with a funny addition spray painted on it'. Replace the letter 'y' with 'q' in the sentence.
Example Output:
a stop sign with a funnq addition spraq painted on it