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

Example Input: Sentence: 'a folding table sitting in a kitchen with a window behind the sink'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a kid is riding a bike down a narrow street'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'the man is surfing through a wave on a yellow surfboard'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
2