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 flat screen tv sitting in the corner of a living room next to a pumpkin'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'one plate holds a slice of cheese pizza and another holds a slice of ham and pineapple pizza'. Count the occurrences of the word 'pizza' in the given sentence.
Example Output:
2