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

Input: Consider Input: Sentence: 'a guy riding a bike close to a car in the street'. Find frequency of the letter 'i'

Output: 4

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

Output: 3

Input: Consider Input: Sentence: 'a man reaching up to catch a frisbee'. Find frequency of the letter 'u'
Output: 1