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

Input: Consider Input: Sentence: 'a man and several white red and blue airplanes'. Find frequency of the letter 'u'

Output: 1


Input: Consider Input: Sentence: 'a little boy that has a toothbrush in his mouth'. Find frequency of the letter 'r'

Output: 1


Input: Consider Input: Sentence: 'a black and white photo of a boardwalk at night'. Find frequency of the letter 'h'


Output: 3