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

Input: Consider Input: Sentence: 'three young people goofing around; one of the guys has a football, the girl has a teddy bear'. Find frequency of the letter 'd'

Output: 3


Input: Consider Input: Sentence: 'people playing wii bowling in a modern library'. Find frequency of the letter 'o'

Output: 3


Input: Consider Input: Sentence: 'dull red train, 54,  between grass and trees'. Find frequency of the letter 'r'


Output: 4