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 a, b, r = "";
  cin >> a >> b;
  int n = a.size();
  sort(a.begin(), a.end());
  sort(b.begin(), b.end());
  reverse(a.begin(), a.end());
  bool ok = 0;
  while (n--) {
    if (!ok) {
      r += a[a.size() - 1];
      a.pop_back();
    } else {
      r += b[b.size() - 1];
      b.pop_back();
    }
    ok = !ok;
  }
  cout << r;
}
