# include <cstdio>
# include <string>
# include <iostream>
using namespace std;

const int N = 255;

string s1, s2;
int f[N], lf[N], rt[N];

void print(char c)
{
	if (!c) return;
	cout << c;
	print(lf[c]);
	print(rt[c]);
}

char dfs(string a, string b)
{
	if (a.size() <= 0)
		return 0;
	char ch = b[1];
	int k = a.find(ch);
	lf[ch] = dfs(a.substr(0, k), b.substr(1, k));
	rt[ch] = dfs(a.substr(k + 1), b.substr(k + 1));
	return ch;
}

int main()
{
	cin >> s1 >> s2;
	char root = dfs(s1, s2);
	print(root);
	return 0;
}

求大佬帮忙看看，全都RE