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

Ex Input:
Sentence: 'a skate park with a young man on a skate board going down a concrete beam'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
4

Ex Input:
Sentence: 'a vehicle applying brakes near a stop sign on a rainy day'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
3

Ex Input:
Sentence: 'a big bird with a huge beak looks out of its cage'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
2