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

Example Input: Sentence: 'a white cat sitting on a bed next to a night stand'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a gentleman walking around the edge of a pool as a bus goes by'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a man standing behind a flat screen tv in a living room with an ironing board'. Count the occurrences of the word 'screen' in the given sentence.
Example Output:
1