How Many Vowels?

Create a function that takes a string and returns the number (count) of vowels contained within it.

Examples

count_vowels("Celebration") ➞ 5

count_vowels("Palm") ➞ 1

count_vowels("Prediction") ➞ 4

Notes

• a, e, i, o, u are considered vowels (not y).
• All test cases are one word and only contain letters.