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 o = "ioi", i = "imo";
  cin >> o >> i;
  sort(o.begin(), o.end());
  sort(i.rbegin(), i.rend());
  int n = o.size();
  string re = o;
  for (int k = 0; k < n; k++) {
    if (k % 2 == 0) {
      re[k] = o[k / 2];
    } else {
      re[k] = i[k / 2];
    }
  }
  cout << re;
}
