#include<iostream>
#include<cstdio>
#include<vector>
#include<cstring>
using namespace std;
const int maxn = 1000+10;
char p[maxn], m[maxn], b[maxn];
int n;

struct node {
    struct node *l, *r;
    char c;
    node(char _c) {
        c = _c;
        this->l = NULL;
        this
 
->r = NULL;
    }
};

node* bit(char *p, char *m, int len) { // 根結點，將二叉樹一分為二
    int pos=-1;
    if (len == 0)
        return NULL;

    for (int i=0; i<len; i++) {
        if (p[0] == m[i]) { //查詢根結點
            pos = i;
            break;
        }
    }
    node *root = new node(p[0]);
    root->l = bit(p+1
 
, m, pos);
    root->r = bit(p+pos+1, m+pos+1, len-pos-1);
    return root;
}

void post(node *root) {
    if (root == NULL)
        return ;
    post(root->l);
    post(root->r);
    printf("%c", root->c);
}

int main() {
    while (scanf("%s%s", p, m)) {
        n = strlen(p);
        node *root =NULL;
        root = bit(p, m, n);
        post(root);
        printf
 
("\n");
    }
    return 0;
}