instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'four people are playing an interesting game in the park'. Replace the letter 'e' with 'x' in the sentence.
answer:
four pxoplx arx playing an intxrxsting gamx in thx park


question:
Sentence: 'a box of a dozen doughnuts all varieties'. Replace the letter 'l' with 'i' in the sentence.
answer:
a box of a dozen doughnuts aii varieties


question:
Sentence: 'ron paul holding a surfboard next to barrack obama'. Replace the letter 'd' with 'u' in the sentence.
answer:

ron paul holuing a surfboaru next to barrack obama