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

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

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

Ex Input:
Sentence: 'a woman is talking on her white phone'. Replace the letter 'w' with 'r' in the sentence.

Ex Output:
a roman is talking on her rhite phone

Ex Input:
Sentence: 'an older woman prepares to eat a sandwich'. Replace the letter 'h' with 'z' in the sentence.

Ex Output:
an older woman prepares to eat a sandwicz