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

Ex Input:
Sentence: 'some brown white black horses dirt a rock and a goat'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
2

Ex Input:
Sentence: 'young teenage boy on his skateboard on the street with people on the curb'. Count the occurrences of the word 'on' in the given sentence.

Ex Output:
3

Ex Input:
Sentence: 'a man riding a skateboard on top of a cement platform'. Count the occurrences of the word 'a' in the given sentence.

Ex Output:
3