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

Ex Input:
Sentence: 'a herd of black cattle grazing and lounging in a green field'. Replace the letter 'a' with 'q' in the sentence.

Ex Output:
q herd of blqck cqttle grqzing qnd lounging in q green field


Ex Input:
Sentence: 'a man stands next to a basketball as it sits on the floor'. Replace the letter 'n' with 'o' in the sentence.

Ex Output:
a mao staods oext to a basketball as it sits oo the floor


Ex Input:
Sentence: 'a couple of elephants are standing in the wild'. Replace the letter 'a' with 'n' in the sentence.

Ex Output:

n couple of elephnnts nre stnnding in the wild