In this task, you need to count the number of words in a sentence that contain the given letter

Ex Input:
Sentence: 'a beautiful old clock tower in a citys historic district'. How many words contain the letter 'a' in the sentence.

Ex Output:
3

Ex Input:
Sentence: 'a pizza with sauce cheese and sausage sitting on a table'. How many words contain the letter 's' in the sentence.

Ex Output:
4

Ex Input:
Sentence: 'this man is skiing down a hill while leaning backwards'. How many words contain the letter 'v' in the sentence.

Ex Output:
0