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

Input: Consider Input: Sentence: 'a group of giraffes walk together by a hill'. Find frequency of the letter 'b'

Output: 1


Input: Consider Input: Sentence: 'man in a sleeping bag on the floor using a laptop computer'. Find frequency of the letter 'i'

Output: 3


Input: Consider Input: Sentence: 'a red stop sign with the word " don't " above it and the word " believing " below it'. Find frequency of the letter 'e'


Output: 7