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

Example Input: Sentence: 'a cake with a missing slice on a floral plate two bowls of fruit and a hand of bananas'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 4

Example Input: Sentence: 'a small bird perched on a branch in a tree'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 3

Example Input: Sentence: 'a peson on a snowboard moving through snowy field'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
2