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

Ex Input:
Sentence: 'this poster is advertising high performance with a girl riding a bicycle and some taxis on the street'. Replace the letter 't' with 'f' in the sentence.

Ex Output:
fhis posfer is adverfising high performance wifh a girl riding a bicycle and some faxis on fhe sfreef

Ex Input:
Sentence: 'a couple walking down a sidewalk next to some graffiti'. Replace the letter 'a' with 'y' in the sentence.

Ex Output:
y couple wylking down y sidewylk next to some gryffiti

Ex Input:
Sentence: 'a bedroom that has a window, bookshelf, and a bed'. Replace the letter 'a' with 'x' in the sentence.

Ex Output:
x bedroom thxt hxs x window, bookshelf, xnd x bed