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 ol, ig;
  cin >> ol >> ig;
  int n = ol.size();
  sort(ol.begin(), ol.end());
  sort(ig.begin(), ig.end(), std::greater<char>());
  int ol_pos = 0, ig_pos = 0;
  for (int i = 0; i < n; ++i) {
    if (!(i % 2)) {
      cout << ol[ol_pos++];
    } else {
      cout << ig[ig_pos++];
    }
  }
  return 0;
}
