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

Input: Consider Input: Sentence: 'a small boy in a high chair eating a cupcake'. Find frequency of the letter 'i'

Output: 4


Input: Consider Input: Sentence: 'children with scissors and construction paper in a school classroom'. Find frequency of the letter 'c'

Output: 6


Input: Consider Input: Sentence: 'an old photo of a man driving a large truck'. Find frequency of the letter 'a'


Output: 5