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

Ex Input:
Sentence: 'a cat sits on the floor next to a purse'. Replace the letter 'a' with 'b' in the sentence.

Ex Output:
b cbt sits on the floor next to b purse


Ex Input:
Sentence: 'a plane getting ready to land on a runway'. Replace the letter 'n' with 'o' in the sentence.

Ex Output:
a plaoe gettiog ready to laod oo a ruoway


Ex Input:
Sentence: 'a man is somewhat hard to be seen in the wave, on his board'. Replace the letter 's' with 'b' in the sentence.

Ex Output:

a man ib bomewhat hard to be been in the wave, on hib board