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

Example Input: Sentence: 'a truck that has pictures painted on it sitting in front of a store'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a picture of a vase with pink flowers in it'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'side review mirror shows dog hanging its head out the window'. Count the occurrences of the word 'the' in the given sentence.
Example Output:
1