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

bccdb
 z
 dfdeed
 aab
 y
 abac

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

public class NamingCompany {

	// variables

	public static char[] oleg, igor;
	public static int olegCur, igorCur;
	public static boolean olegToPlay = true;

	// functions

	public static void main(String[] args) {
		try {
			// readValues
			oleg = in.next().toCharArray();
			igor = in.next().toCharArray();
			olegCur = 0;
			igorCur = igor.length - 1;
			// useFunctions
			Arrays.sort(oleg);
			Arrays.sort(igor);
			// printResult
			for (int i = 0; i < oleg.length; i++) {
				if (olegToPlay) {
					if (oleg[olegCur] >= igor[igorCur] && i < oleg.length - 1) {
						// oleg dont want to play
						System.out.print(igor[igorCur]);
						igorCur--;
						olegToPlay = !olegToPlay;
						i++;
					}
					System.out.print(oleg[olegCur]);
					olegCur++;
					olegToPlay = !olegToPlay;
				} else {
					if (oleg[olegCur] >= igor[igorCur] && i < oleg.length - 1) {
						// igor dont want to play
						System.out.print(oleg[olegCur]);
						olegCur++;
						olegToPlay = !olegToPlay;
						i++;
					}
					System.out.print(igor[igorCur]);
					igorCur--;
					olegToPlay = !olegToPlay;
				}
			}
			in.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	// utils

	public static FastScanner in = new FastScanner(System.in);

	public static class FastScanner {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public FastScanner(InputStream i) {
			reader = new BufferedReader(new InputStreamReader(i));
			tokenizer = new StringTokenizer("");
		}

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

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

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

		public void close() throws IOException {
			reader.close();
		}

	}
}