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

Input: Consider Input: Sentence: 'a snow filled mountain with a guy with ski's'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'a man walking a large elephant down a dirt road'. Find frequency of the letter 'g'

Output: 2


Input: Consider Input: Sentence: 'a postman watching passengers exit a commuter bus'. Find frequency of the letter 'p'


Output: 2