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: 'zebras and antelopes in a field of dried grass'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'a couple of people are riding horses in a village'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'small baby laying down inside a suitcase alone'. How many words start with the letter 'i' in the sentence.
Example Output:
1