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

Example Input: Sentence: 'a little girl is sitting in a suitcase in a library'. Replace the letter 't' with 'l' in the sentence.
Example Output: a lillle girl is silling in a suilcase in a library

Example Input: Sentence: 'a bunch of signs on a pole on the street'. Replace the letter 'c' with 's' in the sentence.
Example Output: a bunsh of signs on a pole on the street

Example Input: Sentence: 'a plate with a grilled cheese sandwich, french fries, tomatoes, and pickles'. Replace the letter 'e' with 'w' in the sentence.
Example Output:
a platw with a grillwd chwwsw sandwich, frwnch friws, tomatows, and picklws