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 woman standing next to another woman in front of a tv'. How many words start with the letter 'a' in the sentence.
Example Output: 3

Example Input: Sentence: 'a black and white photo of a young man riding a horse'. How many words start with the letter 'a' in the sentence.
Example Output: 4

Example Input: Sentence: 'race participants in helmets checking out the local surroundings'. How many words start with the letter 'c' in the sentence.
Example Output:
1