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

Example Input: Sentence: 'a man on a horse in riding gear looking onward'. Replace the letter 'o' with 'h' in the sentence.
Example Output: a man hn a hhrse in riding gear lhhking hnward

Example Input: Sentence: 'a man stands next to a basketball as it sits on the floor'. Replace the letter 'n' with 'o' in the sentence.
Example Output: a mao staods oext to a basketball as it sits oo the floor

Example Input: Sentence: 'a wooden box sitting by the side of a road'. Replace the letter 't' with 'u' in the sentence.
Example Output:
a wooden box siuuing by uhe side of a road