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

Input: Consider Input: Sentence: 'an image of a cautionary construction sign'. Find frequency of the letter 'a'

Output: 5


Input: Consider Input: Sentence: 'two pepperoni pizzas and a cup on a counter'. Find frequency of the letter 'u'

Output: 2


Input: Consider Input: Sentence: 'the man is outside playing frisbee with his dog'. Find frequency of the letter 'l'


Output: 1