TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a red fire hydrant opened and spilling water'. Find frequency of the letter 'd'

SOLUTION: 4

PROBLEM: Sentence: 'a woman swinging a tennis racquet towards a tennis ball'. Find frequency of the letter 'e'

SOLUTION: 3

PROBLEM: Sentence: 'a very small brown colored bathroom with a white toilet'. Find frequency of the letter 't'

SOLUTION:
5