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

Example Input: Sentence: 'a train is moving on a railroad track through a city'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a man sitting in front of a laptop while a standing man looks at the screen'. Count the occurrences of the word 'front' in the given sentence.
Example Output: 1

Example Input: Sentence: 'there are many people smiling and sitting at a table'. Count the occurrences of the word 'are' in the given sentence.
Example Output:
1