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

Example Input: Sentence: 'a woman is holding a bowl of green brocolli'. Replace the letter 'o' with 'w' in the sentence.
Example Output: a wwman is hwlding a bwwl wf green brwcwlli

Example Input: Sentence: 'a photo of a woman milking a brown cow'. Replace the letter 'k' with 'q' in the sentence.
Example Output: a photo of a woman milqing a brown cow

Example Input: Sentence: 'a cat sits on a floor next to a mouse'. Replace the letter 'f' with 'n' in the sentence.
Example Output:
a cat sits on a nloor next to a mouse