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

Input: Consider Input: Sentence: 'a person dressed all in black snowboarding down a slope'. Find frequency of the letter 'e'

Output: 4


Input: Consider Input: Sentence: 'a man with a large grey and black beard and glasses and a tie'. Find frequency of the letter 'e'

Output: 5


Input: Consider Input: Sentence: 'a group of cross country skiers trekking across the snow'. Find frequency of the letter 'r'


Output: 6