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 little boy sitting at a table with a spoon full of food'. How many words start with the letter 's' in the sentence.
Example Output: 2

Example Input: Sentence: 'a woman has just hit the tennis ball with her racket'. How many words start with the letter 't' in the sentence.
Example Output: 2

Example Input: Sentence: 'two women are sitting and eating  while a dog watches them'. How many words start with the letter 'a' in the sentence.
Example Output:
3