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

Example Input: Sentence: 'a cake shaped like a baseball bat and a hat'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a woman cutting cake while another woman is holding a plate'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a motorbike is sitting outside a display window of a clothing shop'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3