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.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 Yousuf
 */
public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(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, InputReader in, PrintWriter out) {

      String str1 = in.next();
      String str2 = in.next();

      char[] strArray = str1.toCharArray();
      Arrays.sort(strArray);
      str1 = new String(strArray);

      strArray = str2.toCharArray();
      Arrays.sort(strArray);
      str2 = new String(strArray);

      str2 = new StringBuilder(str2).reverse().toString();

      int length = 0;
      for (int i = 0; i < str1.length() / 2; i++) {
        out.print(str1.charAt(i));
        out.print(str2.charAt(i));
      }

      if (str1.length() % 2 != 0) {
        out.print(str1.charAt(str1.length() / 2));
      }

      out.println();
    }
  }

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

    public InputReader(InputStream stream) {
      reader = new BufferedReader(new InputStreamReader(stream), 32768);
      //  reader = new BufferedReader(new FileReader("input.txt"));
      tokenizer = null;
    }

    public String next() {
      while (tokenizer == null || !tokenizer.hasMoreTokens()) {
        try {
          tokenizer = new StringTokenizer(reader.readLine());
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
      return tokenizer.nextToken();
    }
  }
}

