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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.IOException;
import java.io.InputStream;
import java.util.InputMismatchException;
import java.util.ArrayList;
import java.util.Collections;

public class companyName {

	static class pair
	{
		char character;
		int value;
		
		public pair(char a){
			this.character=a;
			this.value=character-96;
		}

		
	}

	static class InputReader 
	{
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;
 
        public InputReader(InputStream stream) {
            this.stream = stream;
        }
 
        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
 
        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                        numChars = stream.read(buf);
                } catch (IOException e) {
                        throw new InputMismatchException();
                }
                if (numChars <= 0) {
                        return -1;
                }
            }
            return buf[curChar++];
        }
 
        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }
 
        public interface SpaceCharFilter {
 
            public boolean isSpaceChar(int ch);
        }
 
        public String next() {
            return nextString();
        }
        
        public char nextChar(){
        	int c=read();
        	while (isSpaceChar(c)) {
                c = read();
            }
        	return (char)c;
        }
 
        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }
 
        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
 
        public Long nextLong() {
            return Long.parseLong(nextString());
        }
 
        public Double nextDouble() {
            return Double.parseDouble(nextString());
        }
    }
	
	public static void main(String[] args) {
		
		InputReader s=new InputReader(System.in);
		String oleg=s.nextString(); // oleg goes first
		String igor=s.nextString();
		ArrayList<pair> list1=new ArrayList<>();
		ArrayList<pair> list2=new ArrayList<>();
		for(int i=0;i<oleg.length();i++)
		{
			pair p=new pair(oleg.charAt(i));
			list1.add(p);
		}
		for(int i=0;i<igor.length();i++)
		{
			pair p=new pair(igor.charAt(i));
			list2.add(p);
		}
		
		Collections.sort(list1,(b,a)->(a.value>b.value)?1:(a.value==b.value)?0:-1);
		Collections.sort(list2,(a,b)->(a.value>b.value)?1:(a.value==b.value)?0:-1);
		
		StringBuilder output=new StringBuilder();
		
		int i=0;
		while(i<oleg.length())
		{
			output.append(getOleg(list1));
			i+=1;
			if(i>=oleg.length())
				break;
			output.append(getIgor(list2));
			i+=1;
		}
		
		System.out.println(output);
		
		
		
	}

	private static Object getIgor(ArrayList<pair> list2) {
		char ans=list2.get(list2.size()-1).character;
		list2.remove(list2.size()-1);
		return ans;
	}

	private static Object getOleg(ArrayList<pair> list1) {
		
		char ans=list1.get(list1.size()-1).character;
		list1.remove(list1.size()-1);
		return ans;
	}

}