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

Example Input: Sentence: 'a safari setting at a zoo with two giraffes and a zebra'. Replace the letter 'n' with 'g' in the sentence.
Example Output: a safari settigg at a zoo with two giraffes agd a zebra

Example Input: Sentence: 'a white bathroom with a stand alone sink and a shower curtain'. Replace the letter 'a' with 'm' in the sentence.
Example Output: m white bmthroom with m stmnd mlone sink mnd m shower curtmin

Example Input: Sentence: 'a dog sitting in the living room while watching a tv monitor'. Replace the letter 'n' with 'w' in the sentence.
Example Output:
a dog sittiwg iw the liviwg room while watchiwg a tv mowitor