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: 'there is a plate if food with broccoli fish and a baked potato'. How many words contain the letter 'k' in the sentence.

Ex Output:
1


Ex Input:
Sentence: 'a vase with large sunflowers sitting on a table outside'. How many words contain the letter 'z' in the sentence.

Ex Output:

0