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 Main {
    public static void main(String args[]){
        Scanner scanner=new Scanner(System.in);
        String s=scanner.next();
        char []oleg=s.toCharArray();
        s=scanner.next();
        char []igor=s.toCharArray();
        Arrays.sort(oleg);
        Arrays.sort(igor);
        int i=0;
        for(;i<oleg.length/2;i++){
            System.out.print(oleg[i]);
            System.out.print(igor[igor.length-1-i]);
        }
        if(i*2!=oleg.length){
            System.out.print(oleg[i]);
        }
    }
}