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

Input: Consider Input: Sentence: 'surfboard being displayed in stor window with clothes behind it'. Find frequency of the letter 't'

Output: 4


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 red fire hydrant in a grass area'. Find frequency of the letter 'a'


Output: 6