/*------------------------------------------------------------------------------
 * problem004.cc: Find the passcode to the instructor's office.
**----------------------------------------------------------------------------*/

/* Copyright (c) 2009 Peter Bui. All Rights Reserved.
 *
 * Peter Bui <pbui@cse.nd.edu>
 *
**------------------------------------------------------------------------------
 * Includes
**----------------------------------------------------------------------------*/

#include <cstdlib>
#include <iostream>
#include <set>
#include <string>
#include <vector>

using namespace std;

/*------------------------------------------------------------------------------
 * Type Definitions
**----------------------------------------------------------------------------*/

typedef vector<string>	    Entries;
typedef vector<int>	    Digits;
typedef	vector<set<int> >   Sets;

/*------------------------------------------------------------------------------
 * Macros
**----------------------------------------------------------------------------*/

#define	ctod(c)	((c) - '0')
#define	dtoc(d)	((d) + '0')

/*------------------------------------------------------------------------------
 * Functions
**----------------------------------------------------------------------------*/

void
read_entries(Entries &entries)
{
    string entry;

    while (!getline(cin, entry).eof()) 
	entries.push_back(entry);
}

void
find_digits(Entries &entries, Digits &digits)
{
    int _digits[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

    for (size_t e = 0; e < entries.size(); e++)
	for (size_t s = 0; s < entries[e].size(); s++)
	    _digits[ctod(entries[e][s])]++;

    for (size_t i = 0; i < 10; i++)
	if (_digits[i])
	    digits.push_back(i);
}

void
make_sets(Entries &entries, Digits &digits, Sets &sets)
{
    sets = Sets(digits.size());

    for (size_t e = 0; e < entries.size(); e++) {
	for (size_t d = 0; d < digits.size(); d++) {
	    size_t s = entries[e].find(dtoc(digits[d]));
	    if (s != string::npos)
		for (s = s + 1; s < entries[e].size(); s++)
		    sets[d].insert(ctod(entries[e][s]));
	}
    }
}

/*------------------------------------------------------------------------------
 * Main Execution
**----------------------------------------------------------------------------*/

int
main(int argc, char *argv[]) 
{
    Entries entries;
    Digits  digits;
    Sets    sets;
    string  passcode;

    read_entries(entries);
    find_digits(entries, digits);
    make_sets(entries, digits, sets);

    for (size_t d = 0; d < digits.size(); d++) {
	size_t s;
	for (s = 0; s < sets.size(); s++) 
	    if (sets[s].size() == 0 && digits[s] > 0) 
		break;

	for (size_t ss = 0; ss < sets.size(); ss++)
	    sets[ss].erase(digits[s]);
	
	passcode.push_back(dtoc(digits[s]));
	digits[s] = -1;
    }

    string::reverse_iterator it;
    for (it = passcode.rbegin(); it != passcode.rend(); it++)
	cout << *it;
    cout << endl;

    return (EXIT_SUCCESS);
}

/*------------------------------------------------------------------------------
 * vim: sts=4 sw=4 ts=8 ft=cpp
**----------------------------------------------------------------------------*/