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 swinging a tennis racquet towards a tennis ball'. Find frequency of the letter 'e'

Output: 3

Input: Consider Input: Sentence: 'many different species of sheep in display at a museum'. Find frequency of the letter 'h'

Output: 1

Input: Consider Input: Sentence: 'a small aircraft sits on the tarmac during the day'. Find frequency of the letter 'd'
Output: 2