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

Input: Consider Input: Sentence: 'there is a baseball game on and a few people are watching'. Find frequency of the letter 'i'

Output: 2


Input: Consider Input: Sentence: 'a man in a sweatshirt is taking his own picture'. Find frequency of the letter 'u'

Output: 1


Input: Consider Input: Sentence: 'man holding a baby girl while staring at a frisbee'. Find frequency of the letter 'i'


Output: 5