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.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;
import java.util.StringTokenizer;


/**
 *
 * @author Harsh Vardhan Kumar
 */
public class newMain1 {
    public static boolean eof = false ;
    public static void main(String[] args) {
        //Reader in = new Reader(new BufferedReader(new InputStreamReader(System.in)));
        PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)), true) ;
        Scanner in = new Scanner(System.in) ;
        char[] oleg = in.next().toCharArray() ;
        char[] igor = in.next().toCharArray() ;
        int o = 0 ;
        int i = igor.length-1 ;
        Arrays.sort(oleg);
        Arrays.sort(igor);
        StringBuilder stringBuilder = new StringBuilder();
        
        int turns = oleg.length ;
        while(turns>0) {
            if(oleg[o]<'a' || oleg[o]>'z') {
                o++ ;
            }
            stringBuilder.append(oleg[o]) ;
            o++ ;
            
            turns-- ;
            if(turns>0) {
                if(igor[i]<'a' || igor[i]>'z') {
                    i-- ;
                }
                stringBuilder.append(igor[i]) ;
                i-- ;
                turns-- ;
            }
        }
        System.out.println(stringBuilder);
    }
    static class Reader {
        private static BufferedReader b ;
        public static String line ;
        public Reader() {
        }

        public Reader(BufferedReader b) {
            this.b = b ;
        }
        private static StringTokenizer st = null;
        public static String next()  {
            
            if(st==null || !st.hasMoreElements()) {
                try { 
                    line = b.readLine() ;
                    if(line==null) {
                        eof = true ; 
                        return null ;
                    }
                    else {
                        st=new StringTokenizer(line);
                    }
                } catch (IOException ex) {
                    
                }
            }
            return st.nextToken() ;
        }
        public static String nextLine()  {
            try {
                return b.readLine() ;
            } catch (IOException ex) {
                
            }
            return line ;
        }
        public static int nextInt()  {
            return Integer.parseInt(next());
        }
        public static long nextLong()  {
            return Long.parseLong(next());
        }
        public static float nextFloat()  {
            return Float.parseFloat(next());
        }
        public void close() throws IOException {
            b.close() ;
        }
        
    }
    
}
