TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'four people are playing an interesting game in the park'. Replace the letter 'e' with 'x' in the sentence.

SOLUTION: four pxoplx arx playing an intxrxsting gamx in thx park

PROBLEM: Sentence: 'a person standing on some skis going through the snow'. Replace the letter 'o' with 'l' in the sentence.

SOLUTION: a persln standing ln slme skis gling thrlugh the snlw

PROBLEM: Sentence: 'a metal clock on the side of a wall'. Replace the letter 'a' with 'x' in the sentence.

SOLUTION:
x metxl clock on the side of x wxll