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

Input: Consider Input: Sentence: 'a toilet sits in a cluttered bathroom next to a sink'. Find frequency of the letter 'a'

Output: 4


Input: Consider Input: Sentence: 'a man with headphones on is hunched over a sink while being recorded'. Find frequency of the letter 'd'

Output: 4


Input: Consider Input: Sentence: 'two men styling one woman's hair as she uses a smart phone'. Find frequency of the letter 's'


Output: 7