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

Input: Consider Input: Sentence: 'a woman is playing an interactive video game'. Find frequency of the letter 't'

Output: 2

Input: Consider Input: Sentence: 'a doll with huge eyes and black hair with blunt bangs holds a red umbrella'. Find frequency of the letter 'e'

Output: 5

Input: Consider Input: Sentence: 'a group of children at a table celebrating birthdays'. Find frequency of the letter 't'
Output: 4