#include<iostream>
using namespace std;
typedef struct node {
    char data;
    struct node* lchild, * rchild;
}node, * Tree;

void createTree(Tree& T, string pre, string in) {
    T = new node;
    T->lchild = NULL;T->rchild = NULL;
    T->data = pre[0];
    if (pre.size() == 1) return;
    int mid = in.find(pre[0]);
    //没有左子树
    if (mid != 0) {
        createTree(T->lchild, pre.substr(1, mid + 1), in.substr(0, mid));
    }
    //没有右子树
    if (mid != in.size() - 1) {
        createTree(T->rchild, pre.substr(mid + 1), in.substr(mid + 1));
    }

}
void postOrder(Tree T) {
    if (T != NULL) {
        postOrder(T->lchild);
        postOrder(T->rchild);
        cout << T->data;
    }
}
int main() {
    string pre, in;
    cin >> pre >> in;
    Tree T;
    createTree(T, pre, in);
    postOrder(T);
}