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

Ex Input:
Sentence: 'young girls with backpacks are standing near stairs that look to go to the subway'. How many words contain the letter 'r' in the sentence.

Ex Output:
4


Ex Input:
Sentence: 'a young boy holds a baseball bat while a man stands next to him'. How many words contain the letter 'p' in the sentence.

Ex Output:
0


Ex Input:
Sentence: 'a man who is sitting on a train looking down'. How many words contain the letter 'z' in the sentence.

Ex Output:

0