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 man in red and black jacket snowboarding on slope'. How many words start with the letter 'o' in the sentence.
Example Output: 1

Example Input: Sentence: 'a little girl wearing silver shoes and a pink outfit standing in the rain holding a blue umbrella'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'a commercial gas stove in a kitchen with people in a dining room beyond'. How many words start with the letter 'k' in the sentence.
Example Output:
1