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 flying through the air on a bicycle'. Find frequency of the letter 'u'

Output: 1


Input: Consider Input: Sentence: 'a woman is looking at sheep off in a field'. Find frequency of the letter 'm'

Output: 1


Input: Consider Input: Sentence: 'underside of a passenger jet flying low to the ground at night'. Find frequency of the letter 'n'


Output: 5