In this task, you need to replace a letter in the sentence with another given letter.
--------
Question: Sentence: 'a brown door that says gentlemen and a toilet'. Replace the letter 'o' with 'f' in the sentence.

Answer: a brfwn dffr that says gentlemen and a tfilet

Question: Sentence: 'a small train is on the tracks by a house'. Replace the letter 'l' with 'x' in the sentence.

Answer: a smaxx train is on the tracks by a house

Question: Sentence: 'donuts displayed with a sign on a wooden table'. Replace the letter 'o' with 'd' in the sentence.

Answer:
ddnuts displayed with a sign dn a wddden table