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

Input: Consider Input: Sentence: 'a red train traveling down train tracks near a forest'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'the street sign is next to a curved road'. Find frequency of the letter 's'

Output: 3


Input: Consider Input: Sentence: 'a white haired woman takes a bite out of a sandwich'. Find frequency of the letter 'u'


Output: 1