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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;

import java.io.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.*;



public class lex
{
    
    public static void main(String args[])
    {
        Scanner sc=new Scanner(System.in);
        String a=sc.next();
        String b=sc.next();
        
        char aa[]=a.toCharArray();
        char bb[]=b.toCharArray();
        
        Arrays.sort(aa);
        Arrays.sort(bb);
        
        String res="";
        
        for(int i=0;i<aa.length;i++)
        {
            res+=aa[i]+""+bb[aa.length-(i+1)];
        
            if(res.length()>=a.length())
                break;
        }
        System.out.println(res.substring(0,aa.length));
        
        
        
        
        
        
    }

}