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

Ex Input:
Sentence: 'a couple of giraffe standing next to each other near  a fence'. Replace the letter 'f' with 'j' in the sentence.

Ex Output:
a couple oj girajje standing next to each other near  a jence


Ex Input:
Sentence: 'there is a stepladder situated over a toilet'. Replace the letter 'r' with 'x' in the sentence.

Ex Output:
thexe is a stepladdex situated ovex a toilet


Ex Input:
Sentence: 'a group of people drive a big bus down the city'. Replace the letter 'c' with 'v' in the sentence.

Ex Output:

a group of people drive a big bus down the vity