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

Input: Consider Input: Sentence: 'a red building with a crowd of people outside it near the water'. Find frequency of the letter 'e'

Output: 7


Input: Consider Input: Sentence: 'a picture of two computers on a table'. Find frequency of the letter 'r'

Output: 2


Input: Consider Input: Sentence: 'a group of elephants walking down a street with people on them'. Find frequency of the letter 't'


Output: 5