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

Input: Consider Input: Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'

Output: 5


Input: Consider Input: Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a small pizza is cooking in an oven'. Find frequency of the letter 'n'


Output: 4