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

Sentence: 'a castle like bed room that has the era of templar knight similarities'. Find frequency of the letter 'm'
3

Sentence: 'a train going over a bridge with some buildings in the background'. Find frequency of the letter 'd'
3

Sentence: 'man in a radio studio wearing a suit in front of a microphone'. Find frequency of the letter 't'
3