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

Input: Consider Input: Sentence: 'an audience watches as a bird spreads its wings'. Find frequency of the letter 'd'

Output: 3


Input: Consider Input: Sentence: 'a woman and a child walking down a street with a kite'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a fat sheep standing in a grass field'. Find frequency of the letter 'd'


Output: 2