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;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author omar
 */
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) {
            String a = in.next();
            String b = in.next();
            char a1[] = a.toCharArray();
            char b1[] = b.toCharArray();
            Arrays.sort(a1);
            Arrays.sort(b1);
            StringBuilder temp = new StringBuilder();
            int count1 = 0;
            int count2 = b1.length - 1;
            char temp2, temp3;
            for (int i = 0; i < a1.length; i++) {
                if (i % 2 == 0) {
                    temp2 = a1[count1];
                    temp.append(temp2);
                    count1++;
                } else {
                    temp3 = b1[count2];
                    temp.append(temp3);
                    count2--;
                }
            }
            out.println(temp);
        }

    }
}

