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

Input: Consider Input: Sentence: 'a picture of two men on a motorcycle in front of a railroad track'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a woman in a tank top reaches out for a frisbee'. Find frequency of the letter 'a'

Output: 6


Input: Consider Input: Sentence: 'a man doing a hand stand in the road while holding a skateboard'. Find frequency of the letter 'i'


Output: 4