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: 'birds are standing in a row on a wooden railing'. How many words start with the letter 'a' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a woman sitting on some stairs by a ball and backpack'. How many words start with the letter 'b' in the sentence.

Ex Output:
3


Ex Input:
Sentence: 'a man riding a skateboard up into the air'. How many words start with the letter 'a' in the sentence.

Ex Output:

3