Create a function that takes a string and returns a string with its letters in alphabetical order.

Examples

alphabet_soup("hello") ➞ "ehllo"

alphabet_soup("edabit") ➞ "abdeit"

alphabet_soup("hacker") ➞ "acehkr"

alphabet_soup("geek") ➞ "eegk"

alphabet_soup("javascript") ➞ "aacijprstv"

Notes

You can assume numbers and punctuation symbols won't be included in test cases. You'll only have to deal with single word, alphabetic characters.