#include <bits/stdc++.h>

using namespace std;

int main (){
	int equalA[64];
	int equalB[64];
	string a,b,res;
	while (getline(cin,a)&&getline(cin,b)){
		memset (equalA,0,sizeof(equalA));
		memset (equalB,0,sizeof(equalB));
		res.clear();
		for (int i = 0 ; i < a.size(); i++){
			equalA[a[i] - 'a'] ++;
		}
		for (int i = 0 ; i < b.size(); ++i){
			equalB[b[i] - 'a'] ++;
		}
		int j;
		for (char i = 'a'; i<= 'z';++i){
			if(equalA[i-'a']&&equalB[i-'a']){
			if (equalA[i-'a']<=equalB[i-'a'])
				j = equalA[i - 'a'];
			else
				j = equalB[i - 'a'];
				while(j!=0){
					cout << i;
					res += i;
					j--;
				}
			}
		}
	cout<< endl;
	}

	return 0;
}