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

Example Input: Sentence: 'a couple wearing a suit and red scarf pose for a picture near a christmas tree'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 4

Example Input: Sentence: 'a young boy in a green baseball uniform holding a baseball bat'. Count the occurrences of the word 'baseball' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a plate full of food covered in gravy sitting on a dinner table'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
2