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(false);
  cin.tie(NULL);
  cout.tie(NULL);
  string a, b;
  cin >> a >> b;
  int l = a.length();
  char o[l + 5], z[l + 5];
  for (int i = 0; i < l; i++) {
    o[i] = a[i];
    z[i] = b[i];
  }
  sort(o, o + l);
  sort(z, z + l);
  string ans = "";
  int i = 0, j = l - 1, cnt = 0;
  while (cnt < l) {
    if (cnt % 2 == 0)
      ans += o[i], i++;
    else
      ans += z[j], j--;
    cnt++;
  }
  cout << ans;
  return 0;
}
