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

Ex Input:
Sentence: 'a guy looking at a tennis ball with a goofy look'. Replace the letter 'a' with 'x' in the sentence.

Ex Output:
x guy looking xt x tennis bxll with x goofy look


Ex Input:
Sentence: 'a white kitchen with bottles and pots on the counter'. Replace the letter 'a' with 'p' in the sentence.

Ex Output:
p white kitchen with bottles pnd pots on the counter


Ex Input:
Sentence: 'a large elephant walking on top of a grass covered field'. Replace the letter 's' with 'r' in the sentence.

Ex Output:

a large elephant walking on top of a grarr covered field