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

bccdb
 z
 dfdeed
 aab
 y
 abac

#include <bits/stdc++.h>
int main() {
  std::istream& is = std::cin;
  std::ostream& os = std::cout;
  std::string s, t, u;
  char ch;
  for (is.get(ch); ch != '\n'; is.get(ch)) s += ch;
  for (is.get(ch); ch != '\n'; is.get(ch)) t += ch;
  std::sort(s.begin(), s.end(), std::greater<char>());
  std::sort(t.begin(), t.end());
  int n = s.length(), m = 0;
  for (; m < n; m++)
    if (!(m % 2)) {
      u += s.back();
      s.resize(s.size() - 1);
    } else {
      u += t.back();
      t.resize(t.size() - 1);
    }
  os << u;
}
