TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a man with a backpack on a motorcycle'. Replace the letter 't' with 'd' in the sentence.

SOLUTION: a man widh a backpack on a modorcycle

PROBLEM: Sentence: 'a street side tree is filled with candles, teddy bears and balloons'. Replace the letter 'e' with 'c' in the sentence.

SOLUTION: a strcct sidc trcc is fillcd with candlcs, tcddy bcars and balloons

PROBLEM: Sentence: 'a group of guys standing on the beach with several of them holding their surfboards'. Replace the letter 'e' with 'd' in the sentence.

SOLUTION:
a group of guys standing on thd bdach with sdvdral of thdm holding thdir surfboards