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

Input: Consider Input: Sentence: 'a man riding a skateboard up the side of a ramp'. Find frequency of the letter 'u'

Output: 1


Input: Consider Input: Sentence: 'a toilet of some sort near a sink of some sort'. Find frequency of the letter 'o'

Output: 7


Input: Consider Input: Sentence: 'a group of young men playing a game of frisbee'. Find frequency of the letter 'u'


Output: 2