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: 'young lady holding an umbrella while standing at a pond'. How many words start with the letter 'y' in the sentence.
Example Output: 1

Example Input: Sentence: 'a soccer player running and kicking a soccer ball during a match'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'a group of people and cow outside of a hut'. How many words start with the letter 'a' in the sentence.
Example Output:
3