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

Example Input: Sentence: 'a giraffe looking over a fence and another reaching over the fence'. Replace the letter 'l' with 'h' in the sentence.
Example Output: a giraffe hooking over a fence and another reaching over the fence

Example Input: Sentence: 'the kitchen counter has a pitcher of lime juice'. Replace the letter 'h' with 'p' in the sentence.
Example Output: tpe kitcpen counter pas a pitcper of lime juice

Example Input: Sentence: 'a herd of cattle standing on top of a lush green hillside'. Replace the letter 'f' with 's' in the sentence.
Example Output:
a herd os cattle standing on top os a lush green hillside