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

Input: Consider Input: Sentence: 'a white police vehicle parked on a paved street'. Find frequency of the letter 'a'

Output: 4


Input: Consider Input: Sentence: 'a double parking meter is decorated with a picture of a girl with wings on her feet'. Find frequency of the letter 'r'

Output: 6


Input: Consider Input: Sentence: 'a man in glasses using his laptop computer'. Find frequency of the letter 'u'


Output: 2