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

Example Input: Sentence: 'a group of kites flying in a blue cloudy sky'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a man kneeling down next to a suitcase touching his necklace'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'two people standing in the sand together flying a kite on the beach'. Count the occurrences of the word 'on' in the given sentence.
Example Output:
1