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;
char s1[1000005], s2[1000005];
int i;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> s1 >> s2;
  int len = strlen(s1);
  sort(s1, s1 + len);
  sort(s2, s2 + len);
  for (i = 0; i < len / 2; ++i) {
    cout << s1[i] << s2[len - i - 1];
  }
  if (len % 2 != 0) cout << s1[i];
  return 0;
}
