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

[Q]: Sentence: 'a couple walking down a sidewalk next to some graffiti'. Replace the letter 'a' with 'y' in the sentence.
[A]: y couple wylking down y sidewylk next to some gryffiti


[Q]: Sentence: 'a table full of various types of cellphones, pdas and pagers'. Replace the letter 's' with 'f' in the sentence.
[A]: a table full of variouf typef of cellphonef, pdaf and pagerf


[Q]: Sentence: 'two motorcycles parked in a parking lot outside a filling station'. Replace the letter 'a' with 'o' in the sentence.
[A]:
two motorcycles porked in o porking lot outside o filling stotion