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: 'an older airplane flying above buildings and fields'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'the group of people are getting ready to ski down the mountainside'. How many words start with the letter 't' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'young lady sitting on a bicycle rickshaw talking on the phone'. How many words start with the letter 's' in the sentence.

Ex Output:

1