//根据前序中序遍历结果不断递归查找打印出后序遍历结果
//来自POJ2255
#include <iostream>
#include <cstdio>
#include <cstring>
//#include <string>
using namespace std;
void dfs(char*s1, char*s2, int length1, int length2)
{
    if(length1 == 0)
        return;
    char root = s1[0];
    int i;
    for(i = 0; i < length2; i++)
    {
        if(s2[i] == root)
        break;
    }
    dfs(s1+1,s2,i,i+1);
    dfs(s1+i+1,s2+i+1,length1-i-1,length2-i+1);
    printf("%c",root);
} 

int main(void)
{
    char s1[27], s2[27];
    while(cin >> s1 >> s2)
    {
        dfs(s1,s2,strlen(s1),strlen(s2));
        printf("\n");
    }
    return 0;
}
//==================================
//通过前序中序遍历结果生成二叉树再打印
#include<stdio.h>
#include<string.h>
typedef struct BiTNode
{
    char data;
    struct BiTNode *lc,*rc;
}BiTNode,*BiTree;

BiTree CreateBiTree(BiTree T,char* a,char* b,int n)
{
    int i;
    if(n == 0)
        return NULL;
    for(i=0;i<n;i++)
    {
        if(b[i]==a[0])//i为根节点下标
        {
            T->data=a[0];
            T->lc=CreateBiTree(&T[1],&a[1],&b[0],i);
            T->rc=CreateBiTree(&T[i+1],&a[i+1],&b[i+1],n-i-1);
            break;
        }
    }
    return T;
}
 
void last(BiTree q)  //后序遍历 
{
    if(!q) return;
    last(q->lc);
    last(q->rc);
    printf("%c",q->data);
}
 
int main()
{
    BiTNode tree[30];
    char a[30],b[30];
    while(scanf("%s%s",a,b)==2)
    {
        memset(tree,'\0',sizeof(tree));
        CreateBiTree(tree,a,b,strlen(a));
        last(tree);
        printf("\n");
    }
    return 0;
}