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 and several white red and blue airplanes'. Find frequency of the letter 'u'

Output: 1

Input: Consider Input: Sentence: 'a couple of people that are on a baseball field'. Find frequency of the letter 'c'

Output: 1

Input: Consider Input: Sentence: 'a man outside in the snowing getting ready to ski'. Find frequency of the letter 't'
Output: 5