#include<bits/stdc++.h>
using namespace std;
int n;
int a[100];
string mid, pos;
int  solve(int l, int r, int i) {
	if(l > r)return 0;
	int j = l;
	while(j <= r && i >= 0) 
		if(mid[j] != pos[i])j++;
		else break;
	cout << mid[j];
	solve(l, j - 1, i - r + j - 1);
	solve(j + 1, r, i - 1);				
}
int main() {	
	getline(cin, mid);	
	getline(cin, pos);	
	solve(0, pos.size()-1, pos.size()-1);	
	return 0;
}