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

Input: Consider Input: Sentence: 'a man sitting in front of a laptop computer next to a child'. Find frequency of the letter 'e'

Output: 2


Input: Consider Input: Sentence: 'a person is riding in a cart pulled by a horse'. Find frequency of the letter 'a'

Output: 4


Input: Consider Input: Sentence: 'two boats on shore near an ocean'. Find frequency of the letter 'r'


Output: 2