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() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    string a, b;
    cin >> a >> b;
    sort(a.begin(), a.end());
    sort(b.rbegin(), b.rend());
    int i = 0, j = 0;
    char ans[400000];
    for (int k = 0; k < a.size(); k++) {
      if (k % 2 == 0)
        ans[k] = a[i++];
      else
        ans[k] = b[j++];
    }
    cout << ans;
  }
  return 0;
}
