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

Ex Input:
Sentence: 'street sign titled kittery maine state line in green'. Replace the letter 'e' with 'r' in the sentence.

Ex Output:
strrrt sign titlrd kittrry mainr statr linr in grrrn

Ex Input:
Sentence: 'a mouse and keyboard sitting on a wooden desk'. Replace the letter 'a' with 'n' in the sentence.

Ex Output:
n mouse nnd keybonrd sitting on n wooden desk

Ex Input:
Sentence: 'a large passenger plane is sitting on the tarmac'. Replace the letter 's' with 'k' in the sentence.

Ex Output:
a large pakkenger plane ik kitting on the tarmac