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

Input: Consider Input: Sentence: 'a sailboat is floating near the rocky shore of a beach'. Find frequency of the letter 'o'

Output: 5

Input: Consider Input: Sentence: 'a crowd of people skiing and enjoying the snow'. Find frequency of the letter 'o'

Output: 5

Input: Consider Input: Sentence: 'the people move about and congregate in the public area next to the large white tent'. Find frequency of the letter 'g'
Output: 3