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: 'two laptop computers sitting on top of a white table'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'child sitting on the stop of a truck biting into a hot dog'. Find frequency of the letter 'a'


Output: 2