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

Input: Consider Input: Sentence: 'a young elephant is touching a bigger elephant with its trunk'. Find frequency of the letter 'i'

Output: 5


Input: Consider Input: Sentence: 'a woman throwing a frisbee on a field'. Find frequency of the letter 's'

Output: 1


Input: Consider Input: Sentence: 'a woman sitting on top of a bench with a book'. Find frequency of the letter 'o'


Output: 6