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

Example Input: Sentence: 'a person on a snow board flying through the air'. Replace the letter 'f' with 'n' in the sentence.
Example Output: a person on a snow board nlying through the air

Example Input: Sentence: 'a large table with a green cloth on top'. Replace the letter 'e' with 'i' in the sentence.
Example Output: a largi tabli with a griin cloth on top

Example Input: Sentence: 'whispy clouds and sunset at a traffic intersection'. Replace the letter 't' with 'x' in the sentence.
Example Output:
whispy clouds and sunsex ax a xraffic inxersecxion