#include<bits/stdc++.h>
using namespace std;
string s1,s2;
void ask(string s1,string s2){
	if(s1.size()==0)return ;
	char ch=s1[0];
	int f=s2.find(s1[0]);
	string s1_left=s1.substr(1,f);
	string s2_left=s2.substr(0,f);
	string s1_right=s1.substr(f+1);
	string s2_right=s2.substr(f+1);
	ask(s1_left,s2_left);
	ask(s1_right,s2_right);
	cout<<ch;
}
int main(){
	cin>>s1>>s2;
	ask(s1,s2);
	return 0;
}//写注释