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

Input: Consider Input: Sentence: 'a person is water skiing and there are birds flying around above them'. Find frequency of the letter 'n'

Output: 5


Input: Consider Input: Sentence: 'a view from a bathroom shows an open door'. Find frequency of the letter 'o'

Output: 7


Input: Consider Input: Sentence: 'a man carrying his surfboard into the ocean'. Find frequency of the letter 'a'


Output: 5