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

Input: Consider Input: Sentence: 'some sheep are standing in a grassy field'. Find frequency of the letter 'n'

Output: 3


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: 'the woman is playing with a wii controller'. Find frequency of the letter 't'


Output: 3