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

Example Input: Sentence: 'a man and a child skiing down a mountain on a trail'. Replace the letter 'n' with 'm' in the sentence.
Example Output: a mam amd a child skiimg dowm a moumtaim om a trail

Example Input: Sentence: 'an old photo of group of people nicely dressed around the end of a long table'. Replace the letter 'e' with 'i' in the sentence.
Example Output: an old photo of group of piopli nicily drissid around thi ind of a long tabli

Example Input: Sentence: 'people are gathered in the parking lot around emergency vehicles'. Replace the letter 'r' with 'h' in the sentence.
Example Output:
people ahe gathehed in the pahking lot ahound emehgency vehicles