#include "stdafx.h"

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>


using namespace std;

int main()
{
    string item_string="";
    string curr_string="";
    cin >> item_string >> curr_string;

    vector<char> error_key;
    for (auto ri : item_string)
    {
        char tmp = toupper(ri);
        
        if ((curr_string.find(ri) == string::npos && curr_string.find(tmp) == string::npos))
        {
            auto find_char = find(error_key.begin(), error_key.end(), tmp);
            if (find_char == error_key.cend())
            {
                error_key.push_back(tmp);;
            }
        }
            
    }

    for (auto r : error_key)
    {
        cout << r;
    }

    return 0;
}