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_base::sync_with_stdio(0);
  cin.tie(0);
  int i, j, k, l, m, n, c = 0;
  string r, s, q;
  vector<char> v1, v2;
  cin >> r >> s;
  for (i = 0; r[i]; i++) {
    v1.push_back(r[i]);
    v2.push_back(s[i]);
  }
  sort(v1.begin(), v1.end());
  sort(v2.begin(), v2.end());
  l = r.size();
  for (i = 0, j = s.size() - 1, k = 1; k <= l; k++) {
    if (c == 0) {
      q += v1[i];
      c = 1;
      i++;
    } else {
      q += v2[j];
      c = 0;
      j--;
    }
  }
  cout << q << endl;
  return 0;
}
