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

Example Input: Sentence: 'a woman holding a child are looking at a cow over a fence'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 4

Example Input: Sentence: 'painting of a ship in grass with lighthouse in background'. Count the occurrences of the word 'in' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a bucket is sitting on the floor of a bathroom'. Count the occurrences of the word 'bathroom' in the given sentence.
Example Output:
1