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

Example Input: Sentence: 'a group of people in a field flying kites on a clear day'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

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 beautiful young lady holding a nintendo wii game controller'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
2