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

Example Input: Sentence: 'a person is holding a bat at a baseball game'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a train going over a bridge that is over water'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'large kites being flown on a windy day at the beach'. Count the occurrences of the word 'at' in the given sentence.
Example Output:
1