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

Ex Input:
Sentence: 'traffic congestion with cars and an electric tram'. Replace the letter 'a' with 'k' in the sentence.

Ex Output:
trkffic congestion with ckrs knd kn electric trkm


Ex Input:
Sentence: 'a couple of brown bears walking across a lush green field'. Replace the letter 'w' with 'o' in the sentence.

Ex Output:
a couple of broon bears oalking across a lush green field


Ex Input:
Sentence: 'some pieces of pizza on a plate with a fork'. Replace the letter 'e' with 'd' in the sentence.

Ex Output:

somd pidcds of pizza on a platd with a fork