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

Input: Consider Input: Sentence: 'a stop sign near a rail road crossing sign'. Find frequency of the letter 'g'

Output: 3


Input: Consider Input: Sentence: 'a bus is driving on the street behind some cars'. Find frequency of the letter 'a'

Output: 2


Input: Consider Input: Sentence: 'a group of people eating at a small dining table'. Find frequency of the letter 'n'


Output: 3