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

Example Input: Sentence: 'giraffe standing on a pile of rocks reaching up to a branch with its mouth'. Replace the letter 'g' with 'n' in the sentence.
Example Output: niraffe standinn on a pile of rocks reachinn up to a branch with its mouth

Example Input: Sentence: 'woman pushing a cart of luggage in a transportation terminal'. Replace the letter 'a' with 'w' in the sentence.
Example Output: womwn pushing w cwrt of luggwge in w trwnsportwtion terminwl

Example Input: Sentence: 'a woman wearing skis poses for the camera'. Replace the letter 'k' with 'z' in the sentence.
Example Output:
a woman wearing szis poses for the camera