TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a shot looks down on a person riding a long board'. Replace the letter 'o' with 'u' in the sentence.

SOLUTION: a shut luuks duwn un a persun riding a lung buard

PROBLEM: Sentence: 'two cats sitting on an office chair next to a desk'. Replace the letter 's' with 'j' in the sentence.

SOLUTION: two catj jitting on an office chair next to a dejk

PROBLEM: Sentence: 'a little girl riding on the back of a brown horse'. Replace the letter 'r' with 'i' in the sentence.

SOLUTION:
a little giil iiding on the back of a biown hoise