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

Input: Consider Input: Sentence: 'an old woman is holding her cat in front of a camera'. Find frequency of the letter 'r'

Output: 3


Input: Consider Input: Sentence: 'a plane with stairs next to it sitting in a large lot'. Find frequency of the letter 'i'

Output: 6


Input: Consider Input: Sentence: 'silhouettes of three propellor aircraft against a blue sky'. Find frequency of the letter 'i'


Output: 3