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

Input: Consider Input: Sentence: 'two metal  benches on an empty train platform'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a white bowl filled with peeled orange slices'. Find frequency of the letter 's'

Output: 2


Input: Consider Input: Sentence: 'adult female helping a child learning to ski'. Find frequency of the letter 'n'


Output: 3