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

Input: Consider Input: Sentence: 'a yellow and green train on a train track in a wooded area'. Find frequency of the letter 'o'

Output: 4

Input: Consider Input: Sentence: 'a woman standing next to a man on a motorcycle in front of a market'. Find frequency of the letter 'l'

Output: 1

Input: Consider Input: Sentence: 'a woman with a phone in her hand laughing'. Find frequency of the letter 'i'
Output: 3