TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a group of people riding on top of snow boarding equipment'. Replace the letter 'e' with 'x' in the sentence.

SOLUTION: a group of pxoplx riding on top of snow boarding xquipmxnt

PROBLEM: Sentence: 'the people are in the library working and studying'. Replace the letter 'r' with 'g' in the sentence.

SOLUTION: the people age in the libgagy wogking and studying

PROBLEM: Sentence: 'two giraffes that are standing in the grass'. Replace the letter 'f' with 'd' in the sentence.

SOLUTION:
two giraddes that are standing in the grass