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

bccdb
 z
 dfdeed
 aab
 y
 abac

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

public class Main
{
	public static void main(String[] args)throws IOException
    {
    	BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
    	String str1=br.readLine();
    	String str2=br.readLine();
    	char ar1[]=new char[str1.length()];
    	char ar2[]=new char[str1.length()];
    	for(int i=0;i<str1.length();i++)
    	{
    		ar1[i]=str1.charAt(i);
    		ar2[i]=str2.charAt(i);
    	}
    	Arrays.sort(ar1);
    	Arrays.sort(ar2);
    	int i=0;
    	int j=str1.length()-1;
    	int count=0;
    	int flag=0;
    	while(count<str1.length())
    	{
    		count++;
    		if(flag==0)
    		{
    		System.out.print(ar1[i]);
    		i++;
    		flag=1;
    	}
    	else if(flag==1)
    	{
    		System.out.print(ar2[j]);
    		j--;
    		flag=0;
    	}
    	}

    	



    }
}