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

Example Input: Sentence: 'a man puts his head on his cat sitting on a suitcase'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'the father and son are looking at the kites flying overhead'. Count the occurrences of the word 'the' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a group of three toilets with a person standing in front of the middle one'. Count the occurrences of the word 'toilets' in the given sentence.
Example Output:
1