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

bccdb
 z
 dfdeed
 aab
 y
 abac

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

public class _414div2Q3
{
    public static void main(String[] args) throws IOException
    {
        FastScanner obj = new FastScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));
		
		
		char[] str = obj.next().toCharArray();
		char[] str2 = obj.next().toCharArray();
		
		Arrays.sort(str);
		Arrays.sort(str2);
		
		int n = str.length;
		int oleg = 0;
		int egor = n-1;
		
		int flag = 1;
		for(int i=0;i<n;i++)
		{
			if(flag==1)
			{
				out.print(str[oleg++]);
				flag = 0;
			}
			else
			{
				out.print(str2[egor--]);
				flag = 1;
			}
		}
		out.close();
		out.close();		
	}
 
   //-----------PrintWriter for faster output---------------------------------
   public static PrintWriter out;
      
   //-----------FastScanner class for faster input----------
   public static class FastScanner {
        BufferedReader br;
        StringTokenizer tokenizer;
 
        public FastScanner() throws IOException {
            br = new BufferedReader(new InputStreamReader(System.in));
            tokenizer = new StringTokenizer(br.readLine().trim());
        }
 
        String next() {
            while (tokenizer == null || !tokenizer.hasMoreElements()) {
                try {
                    tokenizer = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                    }
            }
          return tokenizer.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
      
        int[] nextIntArray() throws IOException {
            String[] line = br.readLine().trim().split(" ");
            int[] out = new int[line.length];
            
            for (int i = 0; i < line.length; i++) {
                out[i] = Integer.valueOf(line[i]);
            }
            return out;
        }
        
        BigInteger nextBigInteger() throws IOException {
            return new BigInteger(next());
        }
        
        String nextLine(){
            String str = "";
	        try {
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
        }
 
   }
   //--------------------------------------------------------
} 