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: 'black and white picture of a steam engine on a flooded track'. Count the occurrences of the word 'picture' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a cake shaped like a baseball bat and a hat'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3