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

Ex Input:
Sentence: 'a person holding a green cell phone in a classroom with many desks'. Replace the letter 'k' with 'w' in the sentence.

Ex Output:
a person holding a green cell phone in a classroom with many desws


Ex Input:
Sentence: 'a couple of horses with carriages at a building'. Replace the letter 'u' with 'm' in the sentence.

Ex Output:
a comple of horses with carriages at a bmilding


Ex Input:
Sentence: 'a stop and go light that is in the foreground with a big building in the background'. Replace the letter 'k' with 'z' in the sentence.

Ex Output:

a stop and go light that is in the foreground with a big building in the baczground