#include <bits/stdc++.h>
#define int long long
using namespace std;

string a, b;

int findEnd(string s, int r) {
	int res;
	for (res = r; ; res--) {
		int i = s.find(b[res]);
		if (i != -1)
			return res;
	}
}

void fn(int l, int r, char c) {
	if (l > r) return;
	cout << c;
	int idx = a.find(c);
	if (idx > l)
		fn(l, idx - 1, b[findEnd(a.substr(l, idx - l), idx - 1)]);
	if (idx < r)
		fn(idx + 1, r, b[findEnd(a.substr(idx + 1, r - idx), r)]);
}

signed main() {
	cin >> a >> b;
	fn(0, b.size() - 1, b.back());
	return 0;
}