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

Example Input: Sentence: 'a cake with chocolate frosting and a cake with white frosting are each in an open box'. Count the occurrences of the word 'frosting' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a bear standing on top a piece of pipe with a chain attached'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a small kitchen with a microwave on top of a refrigerator'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3