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

Input: Consider Input: Sentence: 'a group of cars and house on truck passing in a street'. Find frequency of the letter 'i'

Output: 2


Input: Consider Input: Sentence: 'a group of people standing on grass with a train in the background'. Find frequency of the letter 'n'

Output: 6


Input: Consider Input: Sentence: 'a black and silver motorcycle parked in the road'. Find frequency of the letter 'l'


Output: 3