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

Input: Consider Input: Sentence: 'a teddy bear is sitting on a heart shaped patio chair outside'. Find frequency of the letter 'i'

Output: 6


Input: Consider Input: Sentence: 'a photo of a toilet which is not clean'. Find frequency of the letter 'w'

Output: 1


Input: Consider Input: Sentence: 'two young girls relaxing on their luggage at the airport'. Find frequency of the letter 'a'


Output: 4