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

Example Input: Sentence: 'a pizza is on a cooling rack on a counter'. Count the occurrences of the word 'on' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a black train is on a train track near some foothills'. Count the occurrences of the word 'a' in the given sentence.
Example Output: 2

Example Input: Sentence: 'a man is sitting on the couch and watching tv while holding the channel selector in his hand and a black guitar is sitting in a corner'. Count the occurrences of the word 'in' in the given sentence.
Example Output:
2