bcdef
abbbc
 z
y
 reddit
abcdef
 abc
aaa
 y
z
 cbxz
aaaa

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        String oleg = s.nextLine();
        String igor = s.nextLine();
        List<Character> olegSmbs = new ArrayList<>();
        List<Character> igorSmbs = new ArrayList<>();
        int n = oleg.length();
        for (int i = 0; i < oleg.length(); i++) {
            olegSmbs.add(oleg.charAt(i));
            igorSmbs.add(igor.charAt(i));
        }
        Collections.sort(olegSmbs);
        Collections.sort(igorSmbs);

        String res = "";
        for (int i = 0; i < oleg.length() / 2; i++) {
            res += olegSmbs.get(i);
            res += igorSmbs.get(oleg.length() - 1 - i);
        }
        if (oleg.length() % 2 == 1) {
            res += olegSmbs.get(oleg.length() / 2);
        }
        System.out.println(res);
    }
}