#include<iostream>
using namespace std;

string a,b;

int Solve(int l,int r,int l1,int r1)
{
	if(l>r) return 0;
	if(b[r1]!=0) cout<<b[r1];
	int pos=l;
	while(a[pos]!=b[r1]) ++pos;
	int nr=pos-l;
	Solve(l,pos-1,l1,l1+nr-1);
	Solve(pos+1,r,l1+nr,l1-1);
}

int main()
{
	cin>>a>>b;
	Solve(0,a.length()-1,0,a.length()-1); 
    return 0;
}