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

bccdb
 z
 dfdeed
 aab
 y
 abac

#include <bits/stdc++.h>
using namespace std;
int main() {
  string oleg, igor;
  cin >> oleg >> igor;
  string a, b;
  sort(oleg.begin(), oleg.end());
  sort(igor.begin(), igor.end());
  int n = igor.length();
  if (n % 2 == 0) {
    a = oleg.substr(0, n / 2);
    b = igor.substr(n / 2, n / 2);
  } else {
    a = oleg.substr(0, n / 2 + 1);
    b = igor.substr(n / 2 + 1, n / 2);
  }
  int i = 0, j = b.length() - 1, k = 0;
  int id = a.length() - 1, jd = 0;
  string p;
  for (int i = 0; i < n; i++) p.push_back('a');
  int l = oleg.length() - 1;
  while (k < oleg.length()) {
    if (a[i] < b[j]) {
      if (k % 2 == 0) {
        p[k] = a[i];
        i++;
      } else {
        p[k] = b[j];
        j--;
      }
    } else {
      if (k % 2 == 0) {
        p[l] = a[id];
        l--;
        id--;
      } else {
        p[l] = b[jd];
        l--;
        jd++;
      }
    }
    k++;
  }
  cout << p;
  return 0;
}
