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

Input: Consider Input: Sentence: 'baseball player reaching back as he's about to throw the ball'. Find frequency of the letter 'e'

Output: 5


Input: Consider Input: Sentence: 'a man standing on a tennis court holding a racquet'. Find frequency of the letter 's'

Output: 2


Input: Consider Input: Sentence: 'a person in the street carrying a cart and an umbrella'. Find frequency of the letter 'n'


Output: 5