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

Input: Consider Input: Sentence: 'a giraffe shares a habitat with a zebra, an ostrich, and an okapi'. Find frequency of the letter 'e'

Output: 3


Input: Consider Input: Sentence: 'a man in costume talking on a cell phone'. Find frequency of the letter 'm'

Output: 2


Input: Consider Input: Sentence: 'a man on a skate board rides on a peer'. Find frequency of the letter 'o'


Output: 3