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

bccdb
 z
 dfdeed
 aab
 y
 abac

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;

public class C0508201703 {

    private static void solve(final Input input, final PrintWriter output) throws IOException {
        char[] one = input.next().toCharArray();
        char[] two = input.next().toCharArray();
        Arrays.sort(one);
        Arrays.sort(two);
        char[] result = new char[one.length];
        for (int i = 0, j = 0; i < one.length; i += 2, j++) {
            result[i] = one[j];
        }
        for (int i = 1, j = two.length - 1; i < one.length; i += 2, j--) {
            result[i] = two[j];
        }
        output.println(new String(result));
    }

    public static void main(String[] args) throws IOException {
        try (final PrintWriter output = new PrintWriter(System.out); final Input input = new Input(new BufferedReader(new InputStreamReader(System.in)))) {
            solve(input, output);
        }
    }

    private static class Input implements Closeable {

        private final BufferedReader bufferedReader;
        private final StringBuilder stringBuilder = new StringBuilder();
        private final static char[] SEPERATOR = {'\t', '\n', '\r', ' '};

        public Input(final BufferedReader in) {
            this.bufferedReader = in;
        }

        private boolean isAnySeperator(final char ch) {
            return ch == SEPERATOR[3] || ch == SEPERATOR[1] || ch == SEPERATOR[0] || ch == SEPERATOR[2];
        }

        private boolean isLineSeperator(final char ch) {
            return ch == SEPERATOR[1] || ch == SEPERATOR[2];
        }

        public String next() throws IOException {
            stringBuilder.setLength(0);
            while (true) {
                int c = bufferedReader.read();
                if (c == -1) {
                    return null;
                }
                char ch = (char) c;
                if (!isAnySeperator(ch)) {
                    stringBuilder.append(ch);
                    break;
                }
            }
            while (true) {
                int c = bufferedReader.read();
                char ch = (char) c;
                if (c == -1 || isAnySeperator(ch)) {
                    break;
                }
                stringBuilder.append(ch);
            }
            return stringBuilder.toString();
        }

        public String nextLine() throws IOException {
            stringBuilder.setLength(0);
            while (true) {
                final int c = bufferedReader.read();
                if (c == -1) {
                    return null;
                }
                final char ch = (char) c;
                if (!isLineSeperator(ch)) {
                    stringBuilder.append(ch);
                    break;
                }
            }
            while (true) {
                int c = bufferedReader.read();
                char ch = (char) c;
                if (c == -1 || isLineSeperator(ch)) {
                    break;
                }
                stringBuilder.append(ch);
            }
            return stringBuilder.toString();
        }

        public int nextInt() throws IOException {
            return Integer.parseInt(next(), 10);
        }

        public long nextLong() throws IOException {
            return Long.parseLong(next(), 10);
        }

        public void close() throws IOException {
            bufferedReader.close();
        }
    }
}
