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

Example Input: Sentence: 'a woman and man both inspecting their cellphones'. Replace the letter 'e' with 'h' in the sentence.
Example Output: a woman and man both insphcting thhir chllphonhs

Example Input: Sentence: 'a open entrance leading to a set of closed doors'. Replace the letter 'd' with 'f' in the sentence.
Example Output: a open entrance leafing to a set of closef foors

Example Input: Sentence: 'a green bench sitting up against a brick wall'. Replace the letter 'n' with 'd' in the sentence.
Example Output:
a greed bedch sittidg up agaidst a brick wall