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

Input: Consider Input: Sentence: 'a line of people on motorcycles on the road'. Find frequency of the letter 'e'

Output: 5


Input: Consider Input: Sentence: 'two persons standing outside a moving sub train'. Find frequency of the letter 'a'

Output: 3


Input: Consider Input: Sentence: 'a couple of people that are ordering some food'. Find frequency of the letter 'r'


Output: 3