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

Example Input: Sentence: 'a white dog and a person with an umbrella and red jacket'. Count the occurrences of the word 'and' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a dog catching a frisbee on a baseball field while its owner watches'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a desk with a laptop next to a cutting board'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3