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 small child takes a bite of a donut'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a woman stands in front of the camera in a living room'. Count the occurrences of the word 'in' in the given sentence.
Example Output:
2