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

Example Input: Sentence: 'a little girl holds a tooth brush while her mother stands in the background in a bathroom'. Count the occurrences of the word 'while' in the given sentence.
Example Output: 1

Example Input: Sentence: 'a batter waits for the next pitch during a baseball game'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a bathroom has a bathtub a radiator and a window'. Count the occurrences of the word 'a' in the given sentence.
Example Output:
4

