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

Sentence: 'one woman is arranging the other woman's hair'. Find frequency of the letter 'o'
4

Sentence: 'man riding a skate board down the little board way'. Find frequency of the letter 'k'
1

Sentence: 'a group of skiers gathered on the ski slope getting ready to ski'. Find frequency of the letter 'u'

1