TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a gray and white cat sleeping on top of a laptop computer'. Replace the letter 'l' with 'g' in the sentence.

SOLUTION: a gray and white cat sgeeping on top of a gaptop computer

PROBLEM: Sentence: 'a herd of zebra stand together and eat grass'. Replace the letter 'n' with 'r' in the sentence.

SOLUTION: a herd of zebra stard together ard eat grass

PROBLEM: Sentence: 'a woman in black jacket talking on cellphone and carrying a purse'. Replace the letter 'b' with 'v' in the sentence.

SOLUTION:
a woman in vlack jacket talking on cellphone and carrying a purse