#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_DEPRECATE

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
#include <fstream>
#include <iterator>
#include <bitset>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> Pii;
typedef pair<ll, ll> Pll;

#define FOR(i,n) for(int i = 0; i < (n); i++)
#define sz(c) ((int)(c).size())
#define ten(x) ((int)1e##x)
#define tenll(x) ((ll)1e##x)

int main(){
	int n; cin >> n;
	ull ans = ULLONG_MAX;
	FOR(i, n){
		string s; cin >> s;
		vector<int> v;
		int mx = 0;
		for (auto c : s) {
			int x;
			if ('0' <= c && c <= '9') x = c - '0';
			else x = c - 'A' + 10;
			v.push_back(x);
			mx = max(mx, x);
		}
		mx++;
		ull tmp = 0;
		for (auto b : v) {
			tmp = tmp * mx + b;
		}
		ans = min(ans, tmp);
	}

	cout << ans << endl;
}