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

Example Input: Sentence: 'a cat is watching a computer with a video of a cat'. Replace the letter 't' with 'a' in the sentence.
Example Output: a caa is waaching a compuaer wiah a video of a caa

Example Input: Sentence: 'a herd of black cattle grazing and lounging in a green field'. Replace the letter 'a' with 'q' in the sentence.
Example Output: q herd of blqck cqttle grqzing qnd lounging in q green field

Example Input: Sentence: 'a baseball player on a field throwing a baseball'. Replace the letter 'n' with 'o' in the sentence.
Example Output:
a baseball player oo a field throwiog a baseball