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

bccdb
 z
 dfdeed
 aab
 y
 abac


import java.util.Arrays;
import java.util.Scanner;

public class Codeforces {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);
		char[] a = scan.nextLine().toCharArray();
		char[] b = scan.nextLine().toCharArray();
		Arrays.sort(a);
		Arrays.sort(b);
		int c = 0, d = b.length - 1;
		for(int i = 0; i < a.length; i++){
			if((i & 1) == 0){
				System.out.print(a[c]);
				c++;
			}
			else{
				System.out.print(b[d]);
				d--;
			}
		}
		System.out.println();
	}
}