TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'an old rusty car sits outside of an old building'. Replace the letter 'o' with 'r' in the sentence.

SOLUTION: an rld rusty car sits rutside rf an rld building

PROBLEM: Sentence: 'a young boy in a shopping cart looking at tooth brushes'. Replace the letter 'o' with 'r' in the sentence.

SOLUTION: a yrung bry in a shrpping cart lrrking at trrth brushes

PROBLEM: Sentence: 'a person laying in bed with a pillow over their face'. Replace the letter 'e' with 't' in the sentence.

SOLUTION:
a ptrson laying in btd with a pillow ovtr thtir fact