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;
int n, m, i, j, l, r;
string st;
char ans[1000005];
priority_queue<char> sb;
priority_queue<char, vector<char>, greater<char> > sa;
int main() {
  ios::sync_with_stdio(false);
  ;
  cin >> st;
  for (i = 0; i < st.length(); i++) sa.push(st[i]);
  cin >> st;
  for (i = 0; i < st.length(); i++) sb.push(st[i]);
  n = st.length();
  l = 1;
  r = n;
  memset(ans, '_', sizeof(ans));
  for (i = 1; i <= st.length(); i += 2) {
    ans[l++] = sa.top();
    sa.pop();
    if (i == st.length()) break;
    ans[l++] = sb.top();
    sb.pop();
  }
  for (i = 1; i <= n; i++) cout << ans[i];
  return 0;
}
