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

Input: Consider Input: Sentence: 'a person that is looking out his window'. Find frequency of the letter 'n'

Output: 3


Input: Consider Input: Sentence: 'a row of vintage cars in a grassy field'. Find frequency of the letter 'v'

Output: 1


Input: Consider Input: Sentence: 'a man in riding armor poses in front of a motorcycle'. Find frequency of the letter 'n'


Output: 5