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

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

Sentence: 'a couple of people that are petting a horse'. Replace the letter 'e' with 'p' in the sentence.
a couplp of ppoplp that arp pptting a horsp

Sentence: 'two girls holding blue umbrellas wearing shirts and plastic'. Replace the letter 'd' with 'y' in the sentence.

two girls holying blue umbrellas wearing shirts any plastic