In this task, you need to count the occurrences of the given word in the given sentence.

Example Input: Sentence: 'a man standing on some rocks holding a surfboard'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'an orange and white cat rolling around a wooden floor'. Count the occurrences of the word 'cat' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a snowboarder in a gray jacket is doing a trick'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3