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 a[300005], b[300005];
int main() {
  cin >> a >> b;
  int l = strlen(a);
  sort(a, a + l);
  sort(b, b + l);
  char c[l];
  int a1 = 0, b1 = 0;
  for (int i = 0; i < l; i++) {
    if (i % 2) {
      c[i] = b[l - (b1++) - 1];
    } else
      c[i] = a[a1++];
  }
  cout << c << endl;
}
