In this task, you need to count the number of words in a sentence that start with the given letter. Answer with numbers and not words.

Sentence: 'a person sitting on a stone wall using a cellular phone'. How many words start with the letter 's' in the sentence.
2

Sentence: 'birds are standing in a row on a wooden railing'. How many words start with the letter 'a' in the sentence.
3

Sentence: 'red and yellow tulips are in a vase on a table'. How many words start with the letter 'i' in the sentence.

1