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

Ex Input:
Sentence: 'a man is standing on a snowboard, atop a mountain'. Replace the letter 'd' with 'u' in the sentence.

Ex Output:
a man is stanuing on a snowboaru, atop a mountain

Ex Input:
Sentence: 'a woman walks by with a large suitcase and a polka dot umbrella'. Replace the letter 'e' with 'n' in the sentence.

Ex Output:
a woman walks by with a largn suitcasn and a polka dot umbrnlla

Ex Input:
Sentence: 'a woman reading a laptop set on a stove'. Replace the letter 'g' with 'i' in the sentence.

Ex Output:
a woman readini a laptop set on a stove