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

Example Input: Sentence: 'a cat with a purple and red collar sitting in a bowl'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a train on a train track next to a concrete platform'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a close up of a plate of food with a drink'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
3