bcdef
abbbc
 z
y
 reddit
abcdef
 abc
aaa
 y
z
 cbxz
aaaa

bccdb
 z
 dfdeed
 aab
 y
 abac

#include <bits/stdc++.h>
char s1[300033] = {0}, s2[300033] = {0}, out[300033] = {0};
int compare1(const void *a, const void *b) { return (*(char *)a - *(char *)b); }
int compare2(const void *a, const void *b) { return (*(char *)b - *(char *)a); }
int main() {
  int i, l;
  scanf("%s", s1);
  scanf("%s", s2);
  l = strlen(s1);
  qsort(s1, l, sizeof(char), compare1);
  qsort(s2, l, sizeof(char), compare2);
  for (i = 0; i < l; i++) {
    if (i % 2 == 0)
      out[i] = s1[i / 2];
    else
      out[i] = s2[(i - 1) / 2];
  }
  printf("%s\n", out);
  return 0;
}
