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.

Ex Input:
Sentence: 'a cat inside a window looking out near another cat'. How many words start with the letter 'n' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'a person walking on a street with a umbrella'. How many words start with the letter 's' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'a man standing on a mountain top flying an electronic airplane'. How many words start with the letter 'a' in the sentence.

Ex Output:

4