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;
bool chk(char a, char b) { return a > b; }
int main() {
  long long int p, n, q = 0, z, flag = 0, k = 0, l = 0, m = 0, s = 0;
  string s1, s2;
  cin >> s1 >> s2;
  char out[s2.size()];
  p = s2.size() - 1;
  z = s2.size();
  sort(s1.begin(), s1.end());
  sort(s2.begin(), s2.end(), chk);
  n = (s1.size() + 1) / 2;
  s1.erase(s1.begin() + n, s1.end());
  n = s2.size() / 2;
  s2.erase(s2.begin() + n, s2.end());
  m = s1.size() - 1;
  k = s2.size() - 1;
  for (int i = 0; i < z; i++) {
    if (i % 2) {
      if (s2[q] < s1[q]) {
        out[p] = s2[k];
        k--;
        p--;
      } else {
        out[q] = s2[l];
        l++;
        q++;
      }
    } else {
      if (s2.empty()) {
        if (flag)
          out[p] = s1[0];
        else
          out[q] = s1[0];
      } else {
        if (s1[q] > s2[q]) {
          out[p] = s1[m];
          m--;
          p--;
          flag = 1;
        } else {
          out[q] = s1[s];
          s++;
          q++;
          flag = 0;
        }
      }
    }
  }
  for (int i = 0; i < z; i++) cout << out[i];
}
