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

bccdb
 z
 dfdeed
 aab
 y
 abac

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

public class Div2_414_C {
	public static void main(String[] args) throws IOException {
		BufferedInputStream bis = new BufferedInputStream(System.in);
		BufferedReader br = new BufferedReader(new InputStreamReader(bis));
		PrintWriter out = new PrintWriter(System.out);
		String line;
		StringTokenizer st;
		while ((line = br.readLine()) != null && !line.equals("")) {
			int [] olegs = new int[26];
			for (int i = 0; i < line.length(); i++) {
				olegs[line.charAt(i) - 'a']++;
			}
			line = br.readLine();
			int [] igors = new int[26];
			for (int i = 0; i < line.length(); i++) {
				igors[line.charAt(i) - 'a']++;
			}
			int olegsInd = 0, igorsInd = igors.length-1;
			char [] res = new char[line.length()];
			int start = 0, end = res.length-1;
			for (int i = 0;i < res.length;i+=2) {
				while(igors[igorsInd] == 0 && igorsInd >= 0) igorsInd--;
				while(olegs[olegsInd] == 0 && olegsInd < olegs.length) olegsInd++;
				if(olegsInd < igorsInd) {
					res[start++] = (char)('a' + olegsInd);
					if (start < res.length)
						res[start++] = (char)('a' + igorsInd);
				} else {
					res[start++] = (char)('a' + igorsInd);
					if (start < res.length)
						res[start++] = (char)('a' + olegsInd);
				}
				igors[igorsInd]--;
				olegs[olegsInd]--;
			}
			out.println(res);
		}
		out.close();
	}
}