In this task, you need to count the number of words in a sentence that start with the given letter. Answer with numbers and not words.

Example Input: Sentence: 'a cow that is standing in the grass'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'a man riding on top of a wave on a surfboard'. How many words start with the letter 'o' in the sentence.
Example Output: 3

Example Input: Sentence: 'food sitting in a white bowl with a spoon and a glass filled with something to drink'. How many words start with the letter 'a' in the sentence.
Example Output:
4