#include<iostream>
#include<string>
#include<queue>
using namespace std;
char pre[30], mid[30];
queue<char> Q;
int i;
int findInMid()
{
	int j = 0;
	while(pre[i] != mid[j])
		j++;
	i++;
	return j;
}
bool postOrder(int left, int right)
{
	if(left > right)
		return 1;
	int j = findInMid();
	if(postOrder(left, j - 1) && postOrder(j + 1, right))
		Q.push(mid[j]);
}
void print()
{
	while(!Q.empty())
	{
		cout<<Q.front();
		Q.pop();
	}
	cout<<endl;
}
int main()
{
	while(cin>>pre>>mid)
	{
		i = 0;
		postOrder(0, strlen(pre) - 1);
		print();
	}
	return 0;
}