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

Input: Consider Input: Sentence: 'seagulls sit on the posts of a seaside balcony by a clock tower'. Find frequency of the letter 'g'

Output: 1


Input: Consider Input: Sentence: 'a player swings his bat at a baseball game'. Find frequency of the letter 'p'

Output: 1


Input: Consider Input: Sentence: 'a donut display with focus on vanilla party donuts'. Find frequency of the letter 'n'


Output: 4