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], c[300005];
int main() {
  cin >> a >> b;
  int n = strlen(a);
  int aa = 0, bb = n - 1;
  sort(a, a + n);
  sort(b, b + n);
  for (int i = 0; i < n; i++) {
    if (i % 2) {
      c[i] = b[bb];
      bb--;
    } else {
      c[i] = a[aa];
      aa++;
    }
  }
  cout << c;
  return 0;
}
