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 group of four people are riding a ski lift as they ride over the snowy mountain'. How many words start with the letter 'a' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a person is sitting in the grass on a motorcycle'. How many words start with the letter 'i' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'there is a man playing in a game of tennis'. How many words start with the letter 'i' in the sentence.

Ex Output:

2