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

Example Input: Sentence: 'a giraffe standing alone with a low fence behind it'. Replace the letter 't' with 'o' in the sentence.
Example Output: a giraffe soanding alone wioh a low fence behind io

Example Input: Sentence: 'a large white sign with black lettering  leaning against a metal fence'. Replace the letter 'e' with 'j' in the sentence.
Example Output: a largj whitj sign with black ljttjring  ljaning against a mjtal fjncj

Example Input: Sentence: 'a young girl is batting on a field'. Replace the letter 'd' with 'x' in the sentence.
Example Output:
a young girl is batting on a fielx