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

Input: Consider Input: Sentence: 'two men with colorful ties are posing for a picture'. Find frequency of the letter 'r'

Output: 4


Input: Consider Input: Sentence: 'a red fire hydrant opened and spilling water'. Find frequency of the letter 'd'

Output: 4


Input: Consider Input: Sentence: 'an airplane at its terminal as the sun sets'. Find frequency of the letter 'e'


Output: 4