#include<iostream>
#include<algorithm>
#include<cstdio>
#include<string>
#include<deque>
#include<map>
#include<cstring>
using namespace std;

struct node {
    char l, r;
    node() {
        l = r = '*';
    }
    node(char l1, char r1) {
        l = l1;
        r = r1;
    }
};
map<char, node> dic;

string in, post;

inline int searchInTraversal(char v, int s, int e) {
    for (int i = s; i <= e; i++)if (in[i] == v)return i;
    return -1;
}
char buildTree(int is, int ie,int ps,int pe) {
    char father = post[pe];
    if (is == ie && ps == pe) {
        dic[father] = node();
        return father;
    }
    if (is > ie || ps > pe) {
        return '*';
    }
    int posOfF = searchInTraversal(father, is, ie);
    int lTreeLen = posOfF - is;
    char l = buildTree(is, posOfF - 1, ps, ps + lTreeLen - 1);
    char r = buildTree(posOfF + 1, ie, ps + lTreeLen, pe - 1);
    dic[father] = node(l, r);
    return father;
}
void preTraversal(char node) {
    if (node == '*')return;
    cout << node;
    preTraversal(dic[node].l);
    preTraversal(dic[node].r);
}

int main() {
    cin >> in >> post;
    char f=buildTree(0, in.length() - 1, 0, post.length() - 1);
    preTraversal(f);
}