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

Ex Input:
Sentence: 'a giraffe walking in its natural habitat on the savannah'. Replace the letter 't' with 'u' in the sentence.

Ex Output:
a giraffe walking in ius nauural habiuau on uhe savannah


Ex Input:
Sentence: 'there is a big room with furniture and items inside'. Replace the letter 'e' with 'k' in the sentence.

Ex Output:
thkrk is a big room with furniturk and itkms insidk


Ex Input:
Sentence: 'there is animal wall paper on the wall surrounding this toilet'. Replace the letter 'r' with 'x' in the sentence.

Ex Output:

thexe is animal wall papex on the wall suxxounding this toilet