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

Input: Consider Input: Sentence: 'a surfer wipes out on a huge wave'. Find frequency of the letter 'a'

Output: 3


Input: Consider Input: Sentence: 'an area that has surrounded by a metal fence'. Find frequency of the letter 'o'

Output: 1


Input: Consider Input: Sentence: 'a city bus drives down a street as a man walks across a crosswalk'. Find frequency of the letter 'm'


Output: 1