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

Example Input: Sentence: 'a jumbo jet airplane carrying a space shuttle in the air'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a man standing on a white star that is on the floor and he has his hands crossed'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a group of giraffes standing in the grass together'. Count the occurrences of the word 'together' in the given sentence.
Example Output:
1