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 boats floating in the ocean next to a dirty walkway'. How many words start with the letter 't' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'four boats on the sand on the beach'. How many words start with the letter 'o' in the sentence.

Ex Output:
2


Ex Input:
Sentence: 'an image of a black keyboard with 5 color keys and a mouse'. How many words start with the letter 'a' in the sentence.

Ex Output:

4