instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'a man is on a saddled horse with reins'. Replace the letter 's' with 'o' in the sentence.
answer:
a man io on a oaddled horoe with reino

question:
Sentence: 'a fire fighter climbs onto the roof of a market with a ladder'. Replace the letter 'r' with 'k' in the sentence.
answer:
a fike fightek climbs onto the koof of a makket with a laddek

question:
Sentence: 'a couple of people waiting near an electric train'. Replace the letter 'a' with 'j' in the sentence.
answer:
j couple of people wjiting nejr jn electric trjin