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

Input: Consider Input: Sentence: 'a dog has found a rather large stick for playing fetch'. Find frequency of the letter 't'

Output: 3


Input: Consider Input: Sentence: 'a picture of two computers on a table'. Find frequency of the letter 'r'

Output: 2


Input: Consider Input: Sentence: 'the outdoor bench is surrounded by trees, flowers, and other greenery'. Find frequency of the letter 'n'


Output: 4