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

Example Input: Sentence: 'five bags of luggage sitting on to of a floor'. Count the occurrences of the word 'to' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a person on skis standing outside in the snow'. Count the occurrences of the word 'skis' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a red train driving down a train track with a man inside'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3