TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a white plate topped with two sandwich halves and a pile of potatoes chips'. Replace the letter 'o' with 'x' in the sentence.

SOLUTION: a white plate txpped with twx sandwich halves and a pile xf pxtatxes chips

PROBLEM: Sentence: 'two tennis players shaking hands over the net'. Replace the letter 'n' with 'f' in the sentence.

SOLUTION: two teffis players shakifg hafds over the fet

PROBLEM: Sentence: 'a yellow double decker bus on a city street'. Replace the letter 'b' with 'n' in the sentence.

SOLUTION:
a yellow dounle decker nus on a city street