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

Input: Consider Input: Sentence: 'a woman in a messy kitchen with a child'. Find frequency of the letter 'a'

Output: 4

Input: Consider Input: Sentence: 'a blue fire hydrant painted on the bottom of it'. Find frequency of the letter 'h'

Output: 2

Input: Consider Input: Sentence: 'a man sitting alone at a picnic table with a laptop'. Find frequency of the letter 'a'
Output: 8