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.Arrays;
import java.util.Scanner;


public class test  {

public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
String s1=sc.nextLine();
String s2=sc.nextLine();
ArrayList<String> arr1=new ArrayList();
ArrayList<String> arr2=new ArrayList();
char[] ch1=new char[s1.length()];
char[] ch2=new char[s2.length()];
for(int i=0;i<s1.length();i++){
	ch1[i]=s1.charAt(i);
	ch2[i]=s2.charAt(i);
	
}
Arrays.sort(ch1);
Arrays.sort(ch2);

int k=0;int l=s1.length()-1;
for(int i=0;i<s1.length();i++){
	if(i%2==0){
		System.out.print(ch1[k]);
		k++;
		
	}else{
		System.out.print(ch2[l]);
		l--;
	}
}

}}
