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

Example Input: Sentence: 'a red plate and a person is decorating a cake'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a person is holding a bat at a baseball game'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a couple of airplanes sitting on top of a runway'. Count the occurrences of the word 'sitting' in the given sentence.
Example Output:
1