TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a group of people hanging around holding umbrellas'. Replace the letter 'p' with 'f' in the sentence.

SOLUTION: a grouf of feofle hanging around holding umbrellas

PROBLEM: Sentence: 'a large elephant standing outside beside a tree'. Replace the letter 'e' with 'y' in the sentence.

SOLUTION: a largy ylyphant standing outsidy bysidy a tryy

PROBLEM: Sentence: 'a group of people on the beach holding surf boards'. Replace the letter 'o' with 'c' in the sentence.

SOLUTION:
a grcup cf pecple cn the beach hclding surf bcards