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 dog standing near a potted plant outside'. Replace the letter 'a' with 'j' in the sentence.
Example Output: j dog stjnding nejr j potted pljnt outside

Example Input: Sentence: 'a baseball player swinging a bat at a ball'. Replace the letter 's' with 'n' in the sentence.
Example Output:
a baneball player nwinging a bat at a ball