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

Example Input: Sentence: 'a piece of chocolate cake is on a plate with a fork'. Replace the letter 'e' with 's' in the sentence.
Example Output: a piscs of chocolats caks is on a plats with a fork

Example Input: Sentence: 'a bunch of red apples next to a few oranges'. Replace the letter 'n' with 'x' in the sentence.
Example Output: a buxch of red apples xext to a few oraxges

Example Input: Sentence: 'the birds are flying low over the water'. Replace the letter 'e' with 'i' in the sentence.
Example Output:
thi birds ari flying low ovir thi watir