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

Input: Consider Input: Sentence: 'a man that is on his cell phone'. Find frequency of the letter 's'

Output: 2


Input: Consider Input: Sentence: 'a passenger bus that is driving down the street'. Find frequency of the letter 'r'

Output: 3


Input: Consider Input: Sentence: 'a woman in yellow dress standing next to a horse'. Find frequency of the letter 'l'


Output: 2