instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'a couple sits on a bench in the countryside'. Replace the letter 'y' with 'k' in the sentence.
answer:
a couple sits on a bench in the countrkside


question:
Sentence: 'a mouse and keyboard sitting on a wooden desk'. Replace the letter 'a' with 'n' in the sentence.
answer:
n mouse nnd keybonrd sitting on n wooden desk


question:
Sentence: 'a pipe comes out of the sidewalk at the side of this building'. Replace the letter 't' with 'n' in the sentence.
answer:

a pipe comes oun of nhe sidewalk an nhe side of nhis building