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

Input: Consider Input: Sentence: 'a plastic plastic plate topped with three different type of food'. Find frequency of the letter 'l'

Output: 3


Input: Consider Input: Sentence: 'a commuter bus in england by a clock tower building'. Find frequency of the letter 'w'

Output: 1


Input: Consider Input: Sentence: 'a group of male soccer players play on a field on jumps up with the ball in the air'. Find frequency of the letter 's'


Output: 3