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 n[300005], m[300005];
int len1;
int i;
int main() {
  cin >> n >> m;
  len1 = strlen(n);
  sort(n, n + len1);
  sort(m, m + len1);
  for (i = 0; i < len1 / 2; i++) cout << n[i] << m[len1 - i - 1];
  if (len1 % 2 == 1) cout << n[i];
  cout << endl;
}
