#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define each(i,c) for(auto i=(c).begin();i!=(c).end();++i)
#define exist(s,e) ((s).find(e)!=(s).end())
#define clr(a) memset((a),0,sizeof(a))
#define nclr(a) memset((a),-1,sizoef(a))
#define sz(s) (int)((s).size())
#define INRANGE(x,s,e) ((s)<=(x) && (x)<(e))
#define pb push_back
#define MP(x,y) make_pair((x),(y))

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

#define DIGIT	8	// 区切る数字の桁数

class MDC{
public:
	vector<ll> s2i (string s );
	string ladd (vector<ll>, vector<ll> );
	string lsub (vector<ll>, vector<ll> );
	string lmul (vector<ll>, ll );
	string ldiv (vector<ll>, ll );
private:
	string vi2s(vector<ll> );
};

ll s2ll (string s ){
	stringstream ss (s );
	ll res;
	ss >> res;
	return res;
}

string lltos (int n, int flag ){
	stringstream ss;
	ss << n;
	string res;
	ss >> res;

	if (flag ){
		while (res.length() != DIGIT ){
			res = '0' + res;
		} // end while
	} // end if

	return res;
}

// 文字列の数字を DIGIT で区切った数字群に変換
vector<ll> MDC::s2i (string s ){
	vector<ll> res; res.clear();
	
	while (s.length() % DIGIT != 0 ){
		s = '0' + s;
	} // end while

	for (int i = 0; i < s.length(); i += DIGIT ){
		string t = s.substr (i, DIGIT );
		res.push_back (s2ll(t ) );
	} // end for

	return res;
}

// 数字群を文字列に変換
string MDC::vi2s (vector<ll> v ){
	int n = v.size();
	string res = "";
	rep (i, n ) res += lltos(v[i], i );
	
	return res;
}

// 足し算
string MDC::ladd (vector<ll> a, vector<ll> b ){
	reverse (ALL (a ) );
	reverse (ALL (b ) );

	while (a.size() != b.size() ){
		if (a.size() < b.size() )
			a.push_back (0LL );
		else
			b.push_back (0LL );
	} // end while

	int n = a.size();
	ll carry = 0LL;
	vector<ll> res; res.clear();

	rep (i, n ){
		ll c = (a[i] + b[i] ) + carry;
		if (c >= (ll)pow(10, DIGIT ) ){
			c -= (ll)pow(10, DIGIT );
			carry = 1LL;
		}else{
			carry = 0LL;
		} // end if
		res.push_back (c );
	} // end if

	if (carry ){
		res.push_back (carry );
	} // end if

	reverse(ALL (res ) );

	return vi2s(res );
}

// 掛け算
string MDC::lmul (vector<ll> a, ll b ){
	reverse (ALL (a ) );
	int n = a.size();
	ll carry = 0LL;
	vector<ll> res; res.clear();

	rep (i, n ){
		ll d = a[i]*b + carry;
		ll c = d % ((ll)pow(10, DIGIT ) );
		carry = (d - c ) / ((ll)pow(10, DIGIT ) );
		res.push_back (c );
	} // end if

	if (carry ) res.push_back (carry );

	reverse (ALL (res ) );

	return vi2s(res );	
}

map<char,int> digits;

string ladds (string s, string t ){
	MDC MDC;
	vector<ll> a = MDC.s2i (s );
	vector<ll> b = MDC.s2i (t );
	string res = MDC.ladd (a, b );

	return res;
}

string lmuls (ll s, ll b ){
	MDC MDC;
	vector<ll> a; a.push_back (s );
	string res = MDC.lmul (a, b );

	return res;
}


// bit進数から10進数に変換する
string todigit (string s, int bit ){
	int n = s.length();
	reverse (ALL (s ) );
	ll d = 1LL;
	string res = ""; res += '0';
	rep (i, n ){
		string add = lmuls ((ll)digits[s[i]], d );
		res = ladds (res, add );
		d *= (ll)bit;
	} // end rep

	return res;
}


bool max_bool (string s, string t ){
	if (s.length() != t.length() ){
		if (s.length() > t.length() )
			return true;
		else
			return false;
	} // end if

	rep (i, s.length() ){
		if (s[i] == t[i] ) continue;
		return s[i] >= t[i];
	} // end rep

	return true;		
}

string max_s (string s, string t ){
	return (max_bool(s, t ) ? s : t );
}

bool min_bool (string s, string t ){
	if (s.length() != t.length() )
		return (s.length() < t.length() );

	rep (i, s.length() ){
		if (s[i] == t[i] ) continue;
		return s[i] <= t[i];
	} // end rep

	return true;		
}

string min_s (string s, string t ){
	return (min_bool(s, t ) ? s : t );
}

const char order[36] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

int main()
{
	digits.clear();
	rep (i, sizeof(order)/sizeof(order[0] ) ) digits[order[i]] = i;

	ios_base::sync_with_stdio(0);
	int N; cin >> N;

	string res = "";
	rep (i, N ){
		string s; cin >> s;
		int max_digits = 0;
		rep (j, s.length() ){
			max_digits = max (max_digits, digits[s[j]]+1 );
		} // end rep
		string curr = todigit (s, max_digits );
		res = (i == 0 ? curr : min_s (res, curr ) );
//		cerr << s <<'(' << max_digits << ')' << ' ' << curr << endl;
	} // end rep
	cout << res << endl;
				
	return 0;
}