#include <iostream>
#include <string>
using namespace std;
string in, pre, ans;
void dfs(string in, string pre) {
	char c = pre[0];
	for(int i = 0; i < in.size(); i++) {
		if(in[i] == c) {
			string inleft = in.substr(0, i);
			string inright = in.substr(i + 1, in.size() - i - 1);
			string preleft = pre.substr(1, i);
			string preright = pre.substr(i + 1, pre.size() - i - 1);
			dfs(inleft, preleft);
			dfs(inright, preright);
			break;
		}
	}
	cout << c;
}
int main() {
    cin >> in >> pre;
    dfs(in, pre);
    cout << " "; 
    return 0;
}