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: 'a golden haired dog looking out of an open window'. Find frequency of the letter 'd'

Output: 4


Input: Consider Input: Sentence: 'a plate of sprinkled doughnuts with a persons mouth open in the background'. Find frequency of the letter 'd'


Output: 3