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

Sentence: 'the little girl is flying her kite in the field'. Find frequency of the letter 'i'
7

Sentence: 'a dog laying on the back of a boat in the water'. Find frequency of the letter 't'
4

Sentence: 'a blue plate containing a dill pickle, sweet potato chips, baked beans and two hot dogs smothered with relish and mustard'. Find frequency of the letter 'w'

3