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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.DecimalFormat;
import java.util.*;

public class Main2 {

    static long mod = 1000000007L;

    public static void main(String[] args) throws Exception {
        FastScanner scanner = new FastScanner();
        char[] oleg = scanner.nextLine().toCharArray();
        char[] igor = scanner.nextLine().toCharArray();

        Arrays.sort(oleg);
        Arrays.sort(igor);
        char[] igorn = new char[igor.length];
        for (int i = 0; i < igor.length; i++) {
            igorn[i] = igor[igor.length - 1 - i];
        }

        char[] res = new char[oleg.length];
        int oli = 0;
        int igi = 0;
        for (int i = 0; i < res.length; i++) {
            if (i % 2 == 0) {
                res[i] = oleg[oli++];
            } else {
                res[i] = igorn[igi++];
            }
        }
        System.out.println(String.valueOf(res));

    }

    public static class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String nextToken() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            try {
                return br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException();
            }
        }

        int nextInt() {
            return Integer.parseInt(nextToken());
        }

        long nextLong() {
            return Long.parseLong(nextToken());
        }

        double nextDouble() {
            return Double.parseDouble(nextToken());
        }
    }
}
