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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java . util . *; public class NamingCompany {
   

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner in = new Scanner(System.in);
		char oleg[] = in.next().toCharArray(), igor[] = in.next().toCharArray();
		int Oplace = 0, Iplace = igor.length - 1;
		String result = "";
		Arrays.sort(oleg);
		Arrays.sort(igor);
		int Oindex = 0, Iindex = igor.length - 1;
		if (oleg[0] > igor[igor.length - 1]){
			
			for (int i = 0; i < oleg.length; i++){
				
				if (i % 2 == 0){
					result += igor[Iindex];
					--Iindex;
				} else {
					result += oleg[Oindex];
					++Oindex;
				}
			}
		} else {
			for (int i = 0; i < oleg.length; i++){
				
				if (i % 2 == 0){
					result += oleg[Oindex];
					++Oindex;
				} else {
					result += igor[Iindex];
					--Iindex;
				}
		}
		}
			System.out.println(result);
	}

}
