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

vector<char> pre, in, post;
int cnt = 0;
string a,b;

void recons(int l, int r)
{
    if(l >= r) return;
    char root = pre[cnt++];
    int m = distance(in.begin(), find(in.begin(), in.end(), root));
    recons(l, m);
    recons(m + 1, r);
    post.push_back(root);
}

int main()
{
    cin >> a >> b;
    
    for(int i = 0; i < a.size(); i++)
    {
        pre.push_back(a[i]);
        in.push_back(b[i]);
    }
    
    recons(0, a.size());
    
    for(int i = 0; i < a.size(); i++)
        cout << post[i];
        
    return 0;
}