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: 'the men are holding on to surfboards outside'. How many words start with the letter 'o' in the sentence.
Example Output: 2

Example Input: Sentence: 'a woman walks in the street in the rain'. How many words start with the letter 'i' in the sentence.
Example Output: 2

Example Input: Sentence: 'a cat sits on top of a shoe with its nose on the heel'. How many words start with the letter 'o' in the sentence.
Example Output:
3