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.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;


public class Main {
	public static void main(String[] argv) throws FileNotFoundException
	{
		Main m = new Main();
		m.solve();
		
	}

	public void solve () throws FileNotFoundException {
	
	
		InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(new File("A.txt"));


//        String ss = "";
//        for (int i = 0; i < 300000; i++) out.print("x");
//        
//        out.close();
//        System.out.println("OKKKKK");
//        
        String o = in.next();
        String igor = in.next();
        int n = o.length();
        char o1[] = new char[n];
        char i1[] = new char[n];
        
        
        o1 = o.toCharArray();
        i1 = igor.toCharArray();
        Arrays.sort(o1); // small first
        Arrays.sort(i1);
        int a = 0;
        int b = n -1;
                        // large first;
        
        
//        System.out.println(String.valueOf(o1));
        String res = "";
        for (int i = 0; i < n; i++) {
        	if (i % 2 == 0 ) res += o1[a++];
        	else res += i1[b--];
        }
        System.out.println(res);


		
 	}

    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 int nextInt() {
            return Integer.parseInt(next());
        }
        
        public long nextLong() {
        	return Long.parseLong(next());
        }

    }
}