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 wearing a beret while using a laptop computer'. How many words start with the letter 'u' in the sentence.
Example Output: 1

Example Input: Sentence: 'there are people in chairs watching a projection screen'. How many words start with the letter 't' in the sentence.
Example Output: 1

Example Input: Sentence: 'a man is skateboarding down a street'. How many words start with the letter 'd' in the sentence.
Example Output:
1