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

Example Input: Sentence: 'a group of people on a beach flying a kite'. Replace the letter 'p' with 'i' in the sentence.
Example Output: a groui of ieoile on a beach flying a kite

Example Input: Sentence: 'a zebra is eating hay in a fenced enclosure'. Replace the letter 'e' with 'i' in the sentence.
Example Output: a zibra is iating hay in a fincid inclosuri

Example Input: Sentence: 'a small bathroom with a its lights on'. Replace the letter 's' with 'c' in the sentence.
Example Output:
a cmall bathroom with a itc lightc on