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

Example Input: Sentence: 'a group of people are using their laptops in the dark'. Replace the letter 'p' with 'b' in the sentence.
Example Output: a groub of beoble are using their labtobs in the dark

Example Input: Sentence: 'a person and a dog are on a bench'. Replace the letter 'e' with 'r' in the sentence.
Example Output: a prrson and a dog arr on a brnch

Example Input: Sentence: 'the bride about to feed the groom a piece of the wedding cake'. Replace the letter 'b' with 'e' in the sentence.
Example Output:
the eride aeout to feed the groom a piece of the wedding cake