# include<bits/stdc++.h>
using namespace std;


void postorder(string preorder, string inorder)
{
    int len = preorder.length();
    if(len == 0) return;
    if(len == 1)
    {
        cout<<preorder[0];
        return;
    }

    int pos = inorder.find(preorder[0]);

    postorder(preorder.substr(1,pos),inorder.substr(0,pos));
    postorder(preorder.substr(1+pos,len-pos-1),inorder.substr(1+pos,len-pos-1));

    cout<<preorder[0];
}



int main()
{
    string s1, s2;
    cin>>s1>>s2;

    postorder(s1,s2);
}