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 cat inside a window looking out near another cat'. How many words start with the letter 'n' in the sentence.
Example Output: 1

Example Input: Sentence: 'an officer sits on a brown horse on a city street'. How many words start with the letter 'o' in the sentence.
Example Output: 3

Example Input: Sentence: 'a small child is lying on a bed'. How many words start with the letter 'l' in the sentence.
Example Output:
1