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

Input: Consider Input: Sentence: 'two giraffes standing next to some trees'. Find frequency of the letter 'f'

Output: 2


Input: Consider Input: Sentence: 'a silver train crossing the road on tracks'. Find frequency of the letter 'r'

Output: 5


Input: Consider Input: Sentence: 'a white plate with chicken, bread and salad on it'. Find frequency of the letter 'w'


Output: 2