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

Ex Input:
Sentence: 'a person with a scarf on their head sitting on a bench next to flowers with their hand raised'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
3

Ex Input:
Sentence: 'a couple of elephants out in the field having a snack'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
2

Ex Input:
Sentence: 'a baseball player is swinging a bat at a game'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
3