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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.util.*;
import java.io.*;
 
public class Main{
    static BufferedReader br = 
            new BufferedReader(new InputStreamReader(System.in));
    static BufferedWriter bw = 
            new BufferedWriter(new OutputStreamWriter(System.out));
    static StringTokenizer st;
    
    public static void main(String args[]) throws IOException{
        Scanner sc = new Scanner(System.in);
        char[] A, B;
        int L, i;
        A = br.readLine().toCharArray();
        B = br.readLine().toCharArray();
        L = A.length;
        Arrays.sort(A);
        Arrays.sort(B);
        for(i = 0; i < L; i++){
        	if(i%2 == 0){
        		bw.write(A[i/2]+"");
        	}else{
        		bw.write(B[L-1-(i/2)]+"");
        	}
        }
        bw.close();
    }
}