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

Input: Consider Input: Sentence: 'two giraffes standing next to some trees'. Find frequency of the letter 'f'

Output: 2


Input: Consider Input: Sentence: 'a lady is standing near a luggage stand at the air port'. Find frequency of the letter 'a'

Output: 9


Input: Consider Input: Sentence: 'a couple of people playing a game of tennis'. Find frequency of the letter 'p'


Output: 4