In this task, you need to count the number of times the given letter appears in the given sentence.

Sentence: 'flower in a vase full of water sitting on a stand '. Find frequency of the letter 'l'
3

Sentence: 'there is a woman pointing at something with her dog'. Find frequency of the letter 'i'
5

Sentence: 'a girl with her hands up with excitement as a woman brings a cake'. Find frequency of the letter 'r'

3