TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a suitcase is sitting on a sidewalk near trees'. Replace the letter 's' with 'd' in the sentence.

SOLUTION: a duitcade id ditting on a didewalk near treed

PROBLEM: Sentence: 'a ski slope consisting of several people wearing skis and snowboards'. Replace the letter 'e' with 's' in the sentence.

SOLUTION: a ski slops consisting of ssvsral psopls wsaring skis and snowboards

PROBLEM: Sentence: 'a white and brown dog and a brown dog and some people'. Replace the letter 'd' with 'q' in the sentence.

SOLUTION:
a white anq brown qog anq a brown qog anq some people