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

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

Example Input: Sentence: 'a young boy in traditional clothing holding a fan and a cell phone'. Count the occurrences of the word 'boy' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a women that is standing on a tennis court with a rack'. Count the occurrences of the word 'tennis' in the given sentence.
Example Output:
1