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

Ex Input:
Sentence: 'young boy leaping into air with tennis racket with dog below him'. Replace the letter 't' with 'r' in the sentence.

Ex Output:
young boy leaping inro air wirh rennis racker wirh dog below him


Ex Input:
Sentence: 'a book shelf full of books and nick nacks '. Replace the letter 'o' with 'm' in the sentence.

Ex Output:
a bmmk shelf full mf bmmks and nick nacks 


Ex Input:
Sentence: 'the teddy bear is surrounded by plush hands'. Replace the letter 'u' with 'm' in the sentence.

Ex Output:

the teddy bear is smrromnded by plmsh hands