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

Example Input: Sentence: 'a red blanketed bed covered in papers and a computer'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a white and gray cat is in a bathroom sink'. Count the occurrences of the word 'white' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a woman standing under an umbrella on a street and holding a shopping bag on her arm'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3