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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;
import java.util.Collections;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {

            char[] s = in.nextLine().toCharArray();
            char[] t = in.nextLine().toCharArray();

            Character[] temp = new Character[t.length];
            int index = -1;
            for (char T : t)
                temp[++index] = (Character) T;

            Arrays.sort(s);
            Arrays.sort(temp, Collections.reverseOrder());

            int indexs = -1, indext = -1;
            for (int i = 0; i < s.length; ++i) {
                if (i % 2 == 0)
                    out.printf("%s", s[++indexs]);
                else
                    out.printf("%s", temp[++indext]);
            }
        }

    }
}

