#include<bits/stdc++.h>
using namespace std;
string sa,sb,sc;
void find(int ta,int tb,int len) {
    if(len==0) return;
    char root=sa[ta];
    int rti=sb.find(root);
    int siz=rti-tb;
    find(ta+1,tb,siz);
    find(ta+siz+1,rti+1,len-siz-1);
    sc+=root;
}
int main(){
    cin>>sa>>sb;
    find(0,0,sa.size());
    cout<<sc<<endl;
    return 0;
}