#include 
     
      #include 
      
       using namespace std;typedef struct Node{    char data;    Node *lchild,*rchild;}Node,*Bitree;Bitree creat(string s1,string s2){      if(s1.length()==0)        return NULL;    Node *root;    root = new Node;    root->data = s1[0];//第二次做，竟然忘家了     size_t pos = s2.find(s1[0]);    root->lchild=creat(s1.substr(1,pos),s2.substr(0,pos));//从index开始，共num个字符，不是到第num     root->rchild=creat(s1.substr(pos+1),s2.substr(pos+1));    return root;}void postorder(Node *root){    if(root)    {        postorder(root->lchild);        postorder(root->rchild);        cout<
       
        data;    }}int main(){    int i,j,k;    string s1,s2;    while(cin>>s1>>s2)    {        Node *root;        root = creat(s1,s2);        postorder(root);        cout<