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

Example Input: Sentence: 'a big rig is driving through a construction site'. Count the occurrences of the word 'big' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a toddler and baby on a wooden floor scatter with papers'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a group of skiers are gathered together as they get ready to ski'. Count the occurrences of the word 'gathered' in the given sentence.
Example Output:
1