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

Ex Input:
Sentence: 'a crowd stands under a set of lights in the ceiling and one person holds up a cell phone'. Replace the letter 'r' with 'f' in the sentence.

Ex Output:
a cfowd stands undef a set of lights in the ceiling and one pefson holds up a cell phone


Ex Input:
Sentence: 'a couple of kids are sitting in a field'. Replace the letter 't' with 'v' in the sentence.

Ex Output:
a couple of kids are sivving in a field


Ex Input:
Sentence: 'a group of stuffed teddy bears sitting next to each other'. Replace the letter 'i' with 'j' in the sentence.

Ex Output:

a group of stuffed teddy bears sjttjng next to each other