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

Example Input: Sentence: 'a person flying a kite on a busy city street'. Count the occurrences of the word 'on' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a woman is holding a tennis racket on a court'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'electronic equipment including a keyboard on a desk'. Count the occurrences of the word 'including' in the given sentence.
Example Output:
1