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

Example Input: Sentence: 'a batter is batting at a baseball game'. Replace the letter 'b' with 'e' in the sentence.
Example Output: a eatter is eatting at a easeeall game

Example Input: Sentence: 'a red stop signed has been altered to say stop hate'. Replace the letter 'e' with 't' in the sentence.
Example Output: a rtd stop signtd has bttn alttrtd to say stop hatt

Example Input: Sentence: 'a close up of a grassy beach showing an umbrella and wind board'. Replace the letter 'a' with 'f' in the sentence.
Example Output:
f close up of f grfssy befch showing fn umbrellf fnd wind bofrd