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

Input: Consider Input: Sentence: 'two zebras feed on a plant through some wire mesh'. Find frequency of the letter 'o'

Output: 4


Input: Consider Input: Sentence: 'a woman and a child walking down a street with a kite'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a surfer on a surfboard riding the waves'. Find frequency of the letter 'r'


Output: 5