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;
  sort(s1.begin(), s1.end());
  sort(s2.rbegin(), s2.rend());
  string s3 = s1;
  long long int n = s1.size();
  long long int i1 = 0, l1 = (n - 1) / 2;
  long long int i2 = 0, l2 = (n) / 2 - 1;
  long long int i3 = 0, j3 = n - 1;
  for (int i = 0; i < n; i++) {
    if (i % 2 == 0) {
      if (s1[i1] < s2[i2]) {
        s3[i] = s1[i1];
        i1++;
      } else {
        s3[j3] = s1[l1];
        l1--;
        j3--;
      }
    } else {
      if (s1[i1] < s2[i2]) {
        s3[i] = s2[i2];
        i2++;
      } else {
        s3[j3] = s2[l2];
        l2--;
        j3--;
      }
    }
  }
  cout << s3;
}
