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

Example Input: Sentence: 'a building has people in front of it on the sidewalk'. Count the occurrences of the word 'building' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a brown dog sitting in front of a tv in a room'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a bird perched on top of a white coffee cup'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
2