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

Example Input: Sentence: 'a man is somewhat hard to be seen in the wave, on his board'. Replace the letter 's' with 'b' in the sentence.
Example Output: a man ib bomewhat hard to be been in the wave, on hib board

Example Input: Sentence: 'a man and a child skiing down a mountain on a trail'. Replace the letter 'n' with 'm' in the sentence.
Example Output: a mam amd a child skiimg dowm a moumtaim om a trail

Example Input: Sentence: 'two toasted pizza looking food items with greens'. Replace the letter 'a' with 'z' in the sentence.
Example Output:
two tozsted pizzz looking food items with greens