In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a white plate topped with two sandwich halves and a pile of potatoes chips'. Replace the letter 'o' with 'x' in the sentence.
a white plate txpped with twx sandwich halves and a pile xf pxtatxes chips

Sentence: 'a man who is surfing in a wave in the ocean'. Replace the letter 'a' with 'u' in the sentence.
u mun who is surfing in u wuve in the oceun

Sentence: 'a giraffe walking in a grassy area surrounded by wooden fence'. Replace the letter 's' with 'w' in the sentence.
a giraffe walking in a grawwy area wurrounded by wooden fence