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 crowd stands under a set of lights in the ceiling and one person holds up a cell phone'. Replace the letter 'r' with 'f' in the sentence.

SOLUTION: a cfowd stands undef a set of lights in the ceiling and one pefson holds up a cell phone

PROBLEM: Sentence: 'an elephant with hay on its back walking towards a wire fence'. Replace the letter 'a' with 'j' in the sentence.

SOLUTION:
jn elephjnt with hjy on its bjck wjlking towjrds j wire fence