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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.util.*;

public class Qub
{
	public static void main(String[] args) {
		Scanner in=new Scanner(System.in);
		String a=in.nextLine();
		String b=in.nextLine();
		char[] c1=a.toCharArray();
		char[] c2=b.toCharArray();
		Arrays.sort(c1);
		Arrays.sort(c2);
		int n=0;
		int k=b.length()-1;
		for(int i=0;i<a.length();i++) {
			if(i%2==0) {
				System.out.print(c1[n]);
				n++;
			}
			else {
				System.out.print(c2[k]);
				k--;
			}
		}
	}
}
