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

[EX Q]: Sentence: 'a woman holds the reins of a saddled horse'. Find frequency of the letter 'm'
[EX A]: 1

[EX Q]: Sentence: 'a train station with a train pulling into the platform'. Find frequency of the letter 'i'
[EX A]: 6

[EX Q]: Sentence: 'stop sign in the middle of a snowy patch by a road in the forest'. Find frequency of the letter 's'
[EX A]:
4