Unique Sorted Character Concatenation

You are given two strings. Your task is to concatenate the two strings, convert the result to lowercase, and then form a new string containing only the unique characters from the combined string. Finally, you should output these unique characters in sorted order.

Let \(S_1\) and \(S_2\) be the two strings. Define \(T = S_1 \cup S_2\) (after converting both to lowercase). Then the answer is obtained by:

[ \text{result} = \text{sort}({ c : c \in (S_1 \text{ (lowercase)} + S_2 \text{ (lowercase)}) }) ]

For example, if the strings are "hello" and "world", the output should be "dehlorw".

inputFormat

The input consists of two lines. The first line is the first string, and the second line is the second string. Both strings may contain only alphabetic characters.

outputFormat

Output a single line containing the sorted string of unique characters (in lowercase) derived from the concatenation of the two input strings.

hello
world

dehlorw