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

Example Input: Sentence: 'the kitchen has a big screen tv and a lot of counter space'. Replace the letter 'h' with 'z' in the sentence.
Example Output: tze kitczen zas a big screen tv and a lot of counter space

Example Input: Sentence: 'two children who are standing next to a white fire hydrant'. Replace the letter 't' with 'r' in the sentence.
Example Output: rwo children who are sranding nexr ro a whire fire hydranr

Example Input: Sentence: 'three zebra's wagging their tails and eating hay'. Replace the letter 'n' with 'c' in the sentence.
Example Output:
three zebra's waggicg their tails acd eaticg hay