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: 'three people are gathered around sitting on a park bench'. Find frequency of the letter 'g'

Output: 2


Input: Consider Input: Sentence: 'a man is running with a tennis racquet in his hand as a camera operator follows him'. Find frequency of the letter 's'


Output: 5