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

Ex Input:
Sentence: 'an elephant standing on a green grass area'. How many words contain the letter 'm' in the sentence.

Ex Output:
0

Ex Input:
Sentence: 'black and white photo of old man riding a motorcycle'. How many words contain the letter 'n' in the sentence.

Ex Output:
3

Ex Input:
Sentence: 'a woman stands on a sidewalk holding a blue umbrella'. How many words contain the letter 'u' in the sentence.

Ex Output:
2