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

Example Input: Sentence: 'picture of a gothic church with a blue sky in the background'. Replace the letter 'e' with 'i' in the sentence.
Example Output: picturi of a gothic church with a blui sky in thi background

Example Input: Sentence: 'there are people camping and flying kites in a field'. Replace the letter 't' with 'j' in the sentence.
Example Output: jhere are people camping and flying kijes in a field

Example Input: Sentence: 'a plate filled with a sub sandwich and some fries'. Replace the letter 'n' with 's' in the sentence.
Example Output:
a plate filled with a sub sasdwich asd some fries