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 and luggage carts outside of an airplane'. How many words start with the letter 'o' in the sentence.
Example Output: 2

Example Input: Sentence: 'a tall giraffe kissing the bark of a brown tree'. How many words start with the letter 'a' in the sentence.
Example Output: 2

Example Input: Sentence: 'the jumping skateboarder is grabbing the board during a stunt'. How many words start with the letter 't' in the sentence.
Example Output:
2