TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a group of three giraffes standing around a fence'. Replace the letter 't' with 'a' in the sentence.

SOLUTION: a group of ahree giraffes saanding around a fence

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: 'three people are posing for a picture on the beach'. Replace the letter 'h' with 'i' in the sentence.

SOLUTION:
tiree people are posing for a picture on tie beaci