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 s1, s2;
  cin >> s1 >> s2;
  long long n = s1.length();
  multiset<char> m1, m2;
  for (long long i = 0; i < n; i++) {
    m1.insert(s1[i]);
    m2.insert(s2[i]);
  }
  string t1 = "", t2 = "";
  for (multiset<char>::iterator it = m1.begin(); it != m1.end(); it++)
    t1 += (*it);
  for (multiset<char>::iterator it = m2.begin(); it != m2.end(); it++)
    t2 += (*it);
  string fin = "";
  long long i1 = 0, i2 = n - 1;
  for (long long i = 0; i < n;) {
    fin += t1[i1];
    i++;
    if (i < n) fin += t2[i2];
    i++;
    i1++;
    i2--;
  }
  cout << fin << endl;
}
