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

Input: Consider Input: Sentence: 'a surfer is in the middle of an ocean wave'. Find frequency of the letter 'i'

Output: 3


Input: Consider Input: Sentence: 'this yellow fire hydrant sits in a grass field'. Find frequency of the letter 'i'

Output: 5


Input: Consider Input: Sentence: 'man and woman posing in front of a colorful kite'. Find frequency of the letter 'u'


Output: 1