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

Input: Consider Input: Sentence: 'an old glass vase containing flowers on a glass table'. Find frequency of the letter 'b'

Output: 1


Input: Consider Input: Sentence: 'a traffic signal by a wire filled with some birds'. Find frequency of the letter 'e'

Output: 3


Input: Consider Input: Sentence: 'traffic moves in front of buildings and a clock tower'. Find frequency of the letter 'd'


Output: 2