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

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

Output: 1


Input: Consider Input: Sentence: 'the smiling woman is holding a plate of frosted pastries'. Find frequency of the letter 'e'


Output: 4