#include <bits/stdc++.h>

typedef long long ll;
using namespace std;
//1=true 0=false}

int main(){
    ll n, d, r, i;
    string s1,s2;
    char x;
    while(cin>>s1>>s2){
        vector<ll> vet1(200,0);
        vector<ll> vet2(200,0);
        vector<ll> vet3(200,0);
        for(i=0;i<s1.size();i++){
            vet1[s1[i]]++;
        }
        for(i=0;i<s2.size();i++){
            vet2[s2[i]]++;
        }
        for(i=0;i<200;i++){
            vet3[i]=min(vet1[i],vet2[i]);
        }
        for(i=0;i<200;i++){
            for(int j=0;j<vet3[i];j++){
                x=i;
                cout<<x;
            }
        }
        cout<<endl;
    }
}