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

Example Input: Sentence: 'a kid is riding a bike down a narrow street'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a man in red apron preparing food at a table'. Count the occurrences of the word 'apron' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a baby lamb is sitting in the grass next an adult sheep'. Count the occurrences of the word 'sitting' in the given sentence.
Example Output:
1