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

Input: Consider Input: Sentence: 'a lady mixes some things in a blender as people look on'. Find frequency of the letter 'i'

Output: 3


Input: Consider Input: Sentence: 'a airplane view of a big factory some people and cars'. Find frequency of the letter 'f'

Output: 2


Input: Consider Input: Sentence: 'a old red fire hydrain that is next to a street'. Find frequency of the letter 'a'


Output: 4