Simple Letters

Create a function that takes two lowercase strings str1 and str2 of letters from a to z and returns the sorted and longest string containing distinct letters.

Examples

str1 = "mubashir"
str2 = "detabi"

longest_string(str1, str2) ➞ "abdehimrstu"
# Contains sorted and distinct letters of the given strings.

str1 = "abcdefghijklmnopqrstuvwxyz"
str2 = "abcdefghijklmnopqrstuvwxyz"

longest_string(str1, str2) ➞ "abcdefghijklmnopqrstuvwxyz"
# Contains sorted and distinct letters of the given strings.

Notes

N/A