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

Input: Consider Input: Sentence: 'a man riding on the back of a white horse next to other horses'. Find frequency of the letter 'o'

Output: 6

Input: Consider Input: Sentence: 'man in a radio studio wearing a suit in front of a microphone'. Find frequency of the letter 't'

Output: 3

Input: Consider Input: Sentence: 'a giraffe walkinf during the day near a wood fence'. Find frequency of the letter 'e'
Output: 5