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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.*;
import java.util.*;

public class namingcompany {

    static char[] o,ig;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        o = br.readLine().toCharArray();
        ig = br.readLine().toCharArray();
        Arrays.sort(o);
        Arrays.sort(ig);
        char r[] = new char[o.length];
        int nexto=0, nexti=o.length-1;
        for (int i = 0; i < o.length; i++) {
            if (i%2==0)r[i]=o[nexto++];
            else r[i]=ig[nexti--];
        }
        Arrays.sort(r);


        System.out.println(new String(r));
    }

}

