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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.util.*;
import java.io.*;
import java.math.*;
 public class Q1 {

	static ArrayList<Integer> adj[],adj2[];
	static char color[];
	static long mod=1000000007;
	static TreeSet<Integer> ts[];
	static boolean b[],visited[],possible;
	static Stack<Integer> s;
	static int totalnodes,colored,min,minc;
	static int c[];
	static long sum[];
	static HashMap<Integer,Integer> hm;
	public static void main(String[] args) throws IOException {
		
		//Scanner sc=new Scanner(System.in);
		in=new InputReader(System.in);
		out=new PrintWriter(System.out);
		char o[]=in.nextLine().toCharArray();
		char i[]=in.nextLine().toCharArray();
		
		int on=(int)Math.ceil((double)o.length/2);
		int in=(int)Math.floor((double)o.length/2);
		Arrays.sort(o);
		Arrays.sort(i);
		char ans[]=new char[on+in];
		int c1=0,c2=o.length-1;
		int pos=0;
		boolean firstplayer=true;
		//debug(o);
	//	debug(i);
		while(true)
		{
			if(pos>=on+in)
			{
				break;
			}
			else
			{
				if(o[c1]<=i[c2])
				{
					while(pos<on+in)
					{
						ans[pos++]=o[c1++];
						//debug(ans[pos-1]);
						if(pos<on+in)
						ans[pos++]=i[c2--];
			
					}
					
				}
				else
				{
					int l=on+in-pos;int fp1=0,fp2=0;
					if(firstplayer)
					{
						 fp1=(int)Math.ceil((double)l/2);
						 fp2=(int)Math.floor((double)l/2);
					}
				//debug(c1+" "+c2+" "+fp2);
					String s1=new String(o).substring(c1,c1+fp1).toString();
				//	System.out.println(s1);
					
					String s2=new String(i).substring(c2-fp2+1, c2+1).toString();
					//debug(s2);
				
					//String s11=rev(s1);
					//String s22=rev(s2);
					int p1=0,p2=0;
					while(pos<(on+in))
					{
						if(!firstplayer)
						{
							ans[pos++]=s1.charAt(p1);firstplayer=true;p1++;
						}
						else
						{
						//	debug(s2);
						//	debug(s2.charAt(p2));
							if(!s2.equals(""))
							ans[pos++]=s2.charAt(p2);
							firstplayer=false;p2++;
						}
					}
					break;
				}
			}
		}
	out.println(ans);
		out.close();
		}
	
	static InputReader in;
	static PrintWriter out;
static 	int dfs(int j)
	{
		visited[j]=true;
		int max=0;
		for(int i:adj[j])
		{
			if(!visited[i])
			{
				max=Math.max(dfs(i),max);
			}
		}
		c[j]=max+1;
		return c[j];
	}
	/*public static void seive(long n){
		b = new boolean[(int) (n+1)];
	Arrays.fill(b, true);
	
		for(int i = 2;i*i<=n;i++){
			if(b[i]){
				sum[i]=count[i];
			//	System.out.println(sum[i]+" wf");
				for(int p = 2*i;p<=n;p+=i){
					b[p] = false;
					sum[i]+=count[p];  
					//System.out.println(sum[i]);
				}
			}
		
		}
	}*/
	static class Pair implements Comparable<Pair> {
		int i;
		int j;
		int index;
		public Pair(){
			
		}
		public Pair(int u, int v) {
			this.i = u;
			this.j= v;
		}
		public int compareTo(Pair other) {
			
			
					return 0;
		}
		
		/*public String toString() {
			return "[u=" + u + ", v=" + v + "]";
		}*/
	}
	static class Node2{
		Node2 left = null;
		Node2 right = null;
		Node2 parent = null;
		int data;
	}
	
	//binaryStree
	static class BinarySearchTree{
		Node2 root = null;
		int height = 0;
		int max = 0;
		int cnt = 1;
		ArrayList<Integer> parent = new ArrayList<>();
		HashMap<Integer, Integer> hm = new HashMap<>();
		public void insert(int x){
			Node2 n = new Node2();
			n.data = x;
			if(root==null){
				root = n;
			}
			else{
				Node2 temp = root,temp2 = null;
				while(temp!=null){
					temp2 = temp;
					if(x>temp.data) temp = temp.right;
					else temp = temp.left;
				}
				if(x>temp2.data) temp2.right = n;
				else temp2.left = n;
				n.parent = temp2;
				parent.add(temp2.data);
			}
		}
		public Node2 getSomething(int x, int y, Node2 n){
			if(n.data==x || n.data==y) return n;
			else if(n.data>x && n.data<y) return n;
			else if(n.data<x && n.data<y) return getSomething(x,y,n.right);
			else return getSomething(x,y,n.left);
		}
		public Node2 search(int x,Node2 n){
			if(x==n.data){
				max = Math.max(max, n.data);
				return n;
			}
			if(x>n.data){
				max = Math.max(max, n.data);
				return search(x,n.right);
			}
			else{
				max = Math.max(max, n.data);
				return search(x,n.left);
			}
		}
		public int getHeight(Node2 n){
			if(n==null) return 0;
			height = 1+ Math.max(getHeight(n.left), getHeight(n.right));
			return height;
		}
	}
public static void debug(Object... o) {
	System.out.println(Arrays.deepToString(o));
}

public static String rev(String s)
{
	StringBuilder sb=new StringBuilder(s);
	sb.reverse();
	return sb.toString();
}

static long lcm(long a, long b)
{
    return a * (b / gcd(a, b));
}

static long gcd(long a, long b)
{
    while (b > 0)
    {
        long temp = b;
        b = a % b; // % is remainder
        a = temp;
    }
    return a;
}

public static long max(long x, long y, long z){
		if(x>=y && x>=z) return x;
		if(y>=x && y>=z) return y;
		return z;
	}
	static int[] sieve(int n,int[] arr)
	{
	for(int i=2;i*i<=n;i++)
	{
		if(arr[i]==0)
		{
			for(int j=i*2;j<=n;j+=i)
				arr[j]=1;
		}
	}
	return arr;
	}




static class InputReader {

private final InputStream stream;
private final byte[] buf = new byte[8192];
private int curChar, snumChars;
private SpaceCharFilter filter;

public InputReader(InputStream stream) {
  this.stream = stream;
}

public int snext() {
  if (snumChars == -1)
    throw new InputMismatchException();
  if (curChar >= snumChars) {
    curChar = 0;
    try {
      snumChars = stream.read(buf);
    } catch (IOException e) {
      throw new InputMismatchException();
    }
    if (snumChars <= 0)
      return -1;
  }
  return buf[curChar++];
}

public int nextInt() {
  int c = snext();
  while (isSpaceChar(c)) {
    c = snext();
  }
  int sgn = 1;
  if (c == '-') {
    sgn = -1;
    c = snext();
  }
  int res = 0;
  do {
    if (c < '0' || c > '9')
      throw new InputMismatchException();
    res *= 10;
    res += c - '0';
    c = snext();
  } while (!isSpaceChar(c));
  return res * sgn;
}

public long nextLong() {
  int c = snext();
  while (isSpaceChar(c)) {
    c = snext();
  }
  int sgn = 1;
  if (c == '-') {
    sgn = -1;
    c = snext();
  }
  long res = 0;
  do {
    if (c < '0' || c > '9')
      throw new InputMismatchException();
    res *= 10;
    res += c - '0';
    c = snext();
  } while (!isSpaceChar(c));
  return res * sgn;
}

public int[] nextIntArray(int n) {
	 return nextIntArray(n, 0);
	    }
	    
public int[] nextIntArray(int n, int off) {
	 int[] arr = new int[n + off];
	   for (int i = 0; i < n; i++) {
	    arr[i + off] = nextInt();
	    }
	    return arr;
	    }
	    
public long[] nextLongArray(int n) {
return nextLongArray(n, 0);
	    }
        
	public long[] nextLongArray(int n, int off) {
	 long[] arr = new long[n + off];
	 for (int i = 0; i < n; i++) {
		  arr[i + off] = nextLong();
		 }
 return arr;
	}


public String readString() {
  int c = snext();
  while (isSpaceChar(c)) {
    c = snext();
  }
  StringBuilder res = new StringBuilder();
  do {
    res.appendCodePoint(c);
    c = snext();
  } while (!isSpaceChar(c));
  return res.toString();
}

public String nextLine() {
  int c = snext();
  while (isSpaceChar(c))
    c = snext();
  StringBuilder res = new StringBuilder();
  do {
    res.appendCodePoint(c);
    c = snext();
  } while (!isEndOfLine(c));
  return res.toString();
}

public boolean isSpaceChar(int c) {
  if (filter != null)
    return filter.isSpaceChar(c);
  return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
}

private boolean isEndOfLine(int c) {
  return c == '\n' || c == '\r' || c == -1;
}

public interface SpaceCharFilter {
  public boolean isSpaceChar(int ch);
}
}
	
}
