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

Example Input: Sentence: 'a woman is snowboarding down a snowy hill'. Replace the letter 'l' with 'b' in the sentence.
Example Output: a woman is snowboarding down a snowy hibb

Example Input: Sentence: 'vita mix blender with something in it already blended'. Replace the letter 'b' with 'a' in the sentence.
Example Output: vita mix alender with something in it already alended

Example Input: Sentence: 'a bathroom with tiled walls, a sink and cabinets in it'. Replace the letter 's' with 'u' in the sentence.
Example Output:
a bathroom with tiled wallu, a uink and cabinetu in it