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

Ex Input:
Sentence: 'busy city street with pedestrians and cars with lights all around'. Replace the letter 'r' with 'k' in the sentence.

Ex Output:
busy city stkeet with pedestkians and caks with lights all akound


Ex Input:
Sentence: 'a rose that is sitting in a vase'. Replace the letter 'r' with 'j' in the sentence.

Ex Output:
a jose that is sitting in a vase


Ex Input:
Sentence: 'a train traveling down tracks next to a loading area'. Replace the letter 'a' with 'c' in the sentence.

Ex Output:

c trcin trcveling down trccks next to c locding crec