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

Input: Consider Input: Sentence: 'guy leans on truck's hood while taking pics next to parked motorcycles'. Find frequency of the letter 's'

Output: 4


Input: Consider Input: Sentence: 'two bears swim in a blue pool of water'. Find frequency of the letter 'o'

Output: 4


Input: Consider Input: Sentence: 'a boy doing a trick on a skateboard over a rail'. Find frequency of the letter 'y'


Output: 1