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 s[300009], s1[300009], s2[300009];
int main() {
  int i, j, a, b, ts, f = 1, cn = 0, ln;
  scanf("%s %s", s1, s2);
  ln = strlen(s1);
  sort(s1, s1 + ln);
  sort(s2, s2 + ln);
  reverse(s2, s2 + ln);
  for (i = 0; i < ln; i++) {
    if (i % 2 == 0) {
      s[i] = s1[i / 2];
    } else {
      s[i] = s2[i / 2];
    }
  }
  s[ln] = '\0';
  printf("%s\n", s);
  return 0;
}
