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

Example Input: Sentence: 'a man sitting in front of a laptop while a standing man looks at the screen'. Count the occurrences of the word 'front' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a gray and black spotted and striped cat wearing a vest and climbing in a vehicle'. Count the occurrences of the word 'cat' in the given sentence.
Example Output: 1

Example Input: Sentence: 'there is a blue bike parked next to a tree on a sidewalk'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3