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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.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author lebegio
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        MyReader in = new MyReader(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, MyReader in, PrintWriter out) {
            char[] a = in.next().toCharArray();
            char[] b = in.next().toCharArray();
            Arrays.sort(a);
            Arrays.sort(b);
            char[] c = new char[a.length];
            for (int i = 0; i < c.length; i++) {
                if (i % 2 == 0) {
                    c[i] = a[i / 2];
                } else {
                    c[i] = b[b.length - 1 - (i / 2)];
                }
            }
            out.println(c);
        }

    }

    static class MyReader {
        private BufferedReader buffReader;
        private StringTokenizer strTokenizer;
        private static final int SIZE = 32768;

        public MyReader(InputStream inputStream) {
            buffReader = new BufferedReader(new InputStreamReader(inputStream), SIZE);
        }

        public String next() {
            if (strTokenizer == null || !strTokenizer.hasMoreTokens()) {
                try {
                    strTokenizer = new StringTokenizer(buffReader.readLine().trim());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return strTokenizer.nextToken();
        }

    }
}

