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 ladder sitting up against a red wall in a room'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a person is kite surfing on calm water while it is cloudy'. How many words start with the letter 'k' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'people walking and biking along a trail in a park'. How many words start with the letter 'a' in the sentence.

Ex Output:

4