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;
string a;
string b;
string ans = "";
int main() {
  cin >> a;
  cin >> b;
  int len = a.size();
  sort(a.begin(), a.end());
  sort(b.begin(), b.end());
  reverse(b.begin(), b.end());
  int p = 0;
  int q = 0;
  for (int i = 0; i < len; i++) {
    if (i % 2 == 0) {
      ans = ans + a[p];
      p++;
    } else {
      ans = ans + b[q];
      q++;
    }
  }
  cout << ans << "\n";
  return 0;
}
