#include <iostream>
#include <cstdio>
using namespace std;
#define rep(i,a,b) for(int i=a; i<b; i++)

int main(){
	string a,b;
	int x[2][30],f(0);
	while(cin>>a){
		cin>>b;
		rep(i,0,26) x[0][i]=0,x[1][i]=0;
		rep(i,0,a.size()) x[0][a[i]-'a']++;
		rep(i,0,b.size()) x[1][b[i]-'a']++;
		rep(i,0,26) if (x[0][i]&&x[1][i]) while(x[0][i]--&&x[1][i]--) cout<<char(i+'a');
			cout<<endl;

	}
}