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

Example Input: Sentence: 'a small grey bird eating food from paper plates on a picnic table'. Count the occurrences of the word 'small' in the given sentence.
Example Output: 1

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: 'there is a man who is playing a game of tennis'. Count the occurrences of the word 'is' in the given sentence.
Example Output:
2