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

bccdb
 z
 dfdeed
 aab
 y
 abac

//package org.javadov.codeforces.tinkoffFinal;

import java.io.*;
import java.util.Arrays;
import java.util.StringTokenizer;

/**
 * Created by asgar on 2/21/17.
 */

public class TaskC {
    public void solve(int testNumber, InputReader in, PrintWriter out) throws IOException {
        char[] oleg = in.next().toCharArray();
        char[] igor = in.next().toCharArray();

        Arrays.sort(oleg);
        Arrays.sort(igor);

        char[] res = new char[oleg.length];
        for (int i = 0, pfirst = 0, plast = igor.length-1; i < res.length; i++) {
            if ((i&1) == 0) {
                res[i] = oleg[pfirst];
                pfirst++;
            } else {
                res[i] = igor[plast];
                plast--;
            }
        }

        out.println(res);



        return;
    }
    public static void main(String[] args) throws IOException {
        try (InputReader reader = new InputReader(System.in);
             PrintWriter writer = new PrintWriter(System.out)) {
            new TaskC().solve(1, reader, writer);
            writer.flush();
        }
    }

    static class InputReader extends BufferedReader {
        StringTokenizer tokenizer;

        public InputReader(InputStream inputStream) {
            super(new InputStreamReader(inputStream), 32768);
        }

        public InputReader(String filename) {
            super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
        }

        public String next() throws IOException {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                String line = readLine();
                if (line == null)
                    return null;
                tokenizer = new StringTokenizer(line);
            }
            return tokenizer.nextToken();
        }

        public Integer nextInt() throws IOException {
            return Integer.valueOf(next());
        }

        public Long nextLong() throws IOException {
            return Long.valueOf(next());
        }

        public int[] readIntArray (int size) throws IOException {
            int[] array = new int[size];
            for (int i = 0; i < size; i++)
                array[i] = nextInt();
            return array;
        }
    }

    static class FastWriter extends PrintWriter {
        public FastWriter(OutputStream outputStream) {
            super(outputStream);
        }
    }
}


