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

Example Input: Sentence: 'a person on a sandy beach throwing a frisbee'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a red and yellow striped trailer next to a white obelisk statue in a park'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a group of people in a field flying kites'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
2