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

Sentence: 'there are some warning signs on a public toilet'. How many words contain the letter 'a' in the sentence.
3

Sentence: 'a ram standing still in an empty pasture'. How many words contain the letter 'x' in the sentence.
0

Sentence: 'two men are dancing in a parade with brown umbrellas'. How many words contain the letter 'r' in the sentence.
4