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 s1, s2;
  cin >> s1 >> s2;
  sort(s1.begin(), s1.end());
  sort(s2.rbegin(), s2.rend());
  string s = "";
  for (int i = 0; i < s1.size(); i++) {
    if (i % 2 == 0) {
      s += s1[i / 2];
    } else {
      s += s2[(i - 1) / 2];
    }
  }
  cout << s << "\n";
  return 0;
}
