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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.*;
import java.util.*;


public class Main {

    static class Task{
        //////////////////  Solution    /////////////////////////////////////
        public void solve(InputReader in, PrintWriter out) throws Exception {
            char[] oleg = in.next().toCharArray();
            char[] egor = in.next().toCharArray();
            int n = oleg.length;
            Arrays.sort(oleg);
            Arrays.sort(egor);
            int f = 0;
            for (int i = 0, j = 0; j < n;){
                if (f == 0){
                    out.print(oleg[i]);
                    j++;
                }
                else{
                    out.print(egor[n-i-1]);
                    i++;
                    j++;
                }
                f^=1;
            }
        }
        //////////////////////////////////////////////////////////////////////
    }

    public static void main(String[] args) throws Exception{
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task task = new Task();
        task.solve(in, out);
        out.close();
    }

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

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            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();
        }
        public Character nextChar(){
            return next().charAt(0);
        }
        public String nextLine() throws IOException {
            return reader.readLine();
        }
        public long nextLong(){ return Long.parseLong(next()); }
        public int nextInt() {
            return Integer.parseInt(next());
        }
        public double nextDouble() { return Double.parseDouble(next()); }

    }
}