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

Example Input: Sentence: 'the living room is designed with brown and beige colors'. Replace the letter 'i' with 'b' in the sentence.
Example Output: the lbvbng room bs desbgned wbth brown and bebge colors

Example Input: Sentence: 'a person on a snowboard does an air trick'. Replace the letter 'n' with 'o' in the sentence.
Example Output: a persoo oo a soowboard does ao air trick

Example Input: Sentence: 'a small cat sitting on an office chair'. Replace the letter 'l' with 'v' in the sentence.
Example Output:
a smavv cat sitting on an office chair