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

Input: Consider Input: Sentence: 'a bird is standing on the ledge of the building'. Find frequency of the letter 't'

Output: 3


Input: Consider Input: Sentence: 'a construction sign is displayed on a street'. Find frequency of the letter 'i'

Output: 4


Input: Consider Input: Sentence: 'three young men sitting close behind a tasty square cake'. Find frequency of the letter 's'


Output: 4