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

Example Input: Sentence: 'there are many people that are riding a elephant'. Count the occurrences of the word 'are' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a row of red and blue trucks parked in a parking lot'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a person on a beach flying a kite in the sky'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3