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

Input: Consider Input: Sentence: 'a wedding cake with pink roses on a silver plate'. Find frequency of the letter 'a'

Output: 4


Input: Consider Input: Sentence: 'a parking meter painted green with a sign that describes it as not a parking meter'. Find frequency of the letter 's'

Output: 4


Input: Consider Input: Sentence: 'a train is getting ready to leave the train station'. Find frequency of the letter 'n'


Output: 4