instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'a group of giraffe standing on top of a dirt field'. Replace the letter 'a' with 'y' in the sentence.
answer:
y group of giryffe stynding on top of y dirt field

question:
Sentence: 'a big bowl of brown food halfway in a small oven'. Replace the letter 'v' with 'k' in the sentence.
answer:
a big bowl of brown food halfway in a small oken

question:
Sentence: 'a boy skate boarding on the side walk'. Replace the letter 'y' with 'p' in the sentence.
answer:
a bop skate boarding on the side walk