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

Input: Consider Input: Sentence: 'a river with a long dragon boat in it and rowers on the boat in sets of two, along with two other people'. Find frequency of the letter 'h'

Output: 4


Input: Consider Input: Sentence: 'a group of workers washing and cleaning fruits and vegetables'. Find frequency of the letter 'i'

Output: 3


Input: Consider Input: Sentence: 'some people are standing near a fast river'. Find frequency of the letter 'a'


Output: 5