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;
string s_r;
int a, b, c;
string s1, s2;
int main() {
  cin >> s1 >> s2;
  sort(s1.begin(), s1.end());
  sort(s2.begin(), s2.end());
  for (int i = 0; i < s2.length(); ++i) s_r = s_r + " ";
  int i1 = 0, i2 = s2.length() - 1;
  int end = s1.length() - 1;
  int x = 0;
  int N = s1.length();
  for (int i = 0; i <= end;) {
    if (x == 0) {
      if (s1[i1] < s2[i2]) {
        s_r[i] = s1[i1];
        i1++;
        ++i;
      } else {
        s_r[end] = s1[i1 + N / 2 - (N % 2 == 0)];
        end--;
      }
    } else {
      if (s1[i1] < s2[i2]) {
        s_r[i] = s2[i2];
        i2--;
        ++i;
      } else {
        s_r[end] = s2[i2 - N / 2 - (N % 2 == 0)];
        end--;
      }
    }
    x ^= 1;
    --N;
  }
  cout << s_r;
  return 0;
}
