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 ol, ig;
  cin >> ol >> ig;
  int n = ol.size();
  sort(ol.begin(), ol.end());
  sort(ig.begin(), ig.end(), std::greater<char>());
  int ol_pos = 0, ig_pos = 0;
  if (!(n % 2)) {
    for (int i = 0; i < n; i += 2) {
      if (ol[ol_pos] <= ig[ig_pos])
        cout << ol[ol_pos++] << ig[ig_pos++];
      else
        cout << ig[ig_pos++] << ol[ol_pos++];
    }
  } else {
    for (int i = 0; i < n - 1; i += 2) {
      if (ol[ol_pos] <= ig[ig_pos])
        cout << ol[ol_pos++] << ig[ig_pos++];
      else
        cout << ig[ig_pos++] << ol[ol_pos++];
    }
    cout << ol[ol_pos++];
  }
  return 0;
}
