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

Input: Consider Input: Sentence: 'an old boat on a beach near a large body of water'. Find frequency of the letter 'a'

Output: 8


Input: Consider Input: Sentence: 'an commercial airline airplane flies above the clouds'. Find frequency of the letter 'n'

Output: 3


Input: Consider Input: Sentence: 'a geisha in uniform talking on a cell phone'. Find frequency of the letter 'a'


Output: 4