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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.util.*;
import java.io.*;
public class MainClass
{
    public static void main(String args[])throws IOException
    {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        char[] S = in.readLine().toCharArray();
        char[] T = in.readLine().toCharArray();
        Arrays.sort(S);
        Arrays.sort(T);
        StringBuilder stringBuilder = new StringBuilder();
        int turn = 0;
        int i = 0;
        int n = S.length;
        int j = n - 1;
        int moves = S.length;
        int movesForOleg = (moves + 1) / 2;
        int movesForIgor = moves / 2;
        if (turn == 1)
        {
            int temp = movesForIgor;
            movesForIgor = movesForOleg;
            movesForOleg = temp;
        }
        int pointerInT = j - movesForIgor + 1;
        int pointerInS = i + movesForOleg - 1;
        StringBuilder stringBuilder1 = new StringBuilder();
        while (moves-- > 0)
        {
            if (turn == 0)
            {
                stringBuilder1.append(S[pointerInS--]);
                turn = 1;
            }
            else
            {
                stringBuilder1.append(T[pointerInT++]);
                turn = 0;
            }
        }
        stringBuilder1 = stringBuilder1.reverse();
        stringBuilder.append(stringBuilder1);
        System.out.println(stringBuilder);
    }
}
class Reader
{
    final private int BUFFER_SIZE = 1 << 16;
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;

    public Reader()
    {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public Reader(String file_name) throws IOException
    {
        din = new DataInputStream(new FileInputStream(file_name));
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public String readLine() throws IOException
    {
        byte[] buf = new byte[64]; // line length
        int cnt = 0, c;
        while ((c = read()) != -1)
        {
            if (c == '\n')
                break;
            buf[cnt++] = (byte) c;
        }
        return new String(buf, 0, cnt);
    }

    public int nextInt() throws IOException
    {
        int ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do
        {
            ret = ret * 10 + c - '0';
        }  while ((c = read()) >= '0' && c <= '9');

        if (neg)
            return -ret;
        return ret;
    }

    public long nextLong() throws IOException
    {
        long ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');
        if (neg)
            return -ret;
        return ret;
    }

    public double nextDouble() throws IOException
    {
        double ret = 0, div = 1;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();

        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');

        if (c == '.')
        {
            while ((c = read()) >= '0' && c <= '9')
            {
                ret += (c - '0') / (div *= 10);
            }
        }

        if (neg)
            return -ret;
        return ret;
    }

    private void fillBuffer() throws IOException
    {
        bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
        if (bytesRead == -1)
            buffer[0] = -1;
    }

    private byte read() throws IOException
    {
        if (bufferPointer == bytesRead)
            fillBuffer();
        return buffer[bufferPointer++];
    }

    public void close() throws IOException
    {
        if (din == null)
            return;
        din.close();
    }
}