#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <complex>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int v, w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

int main() {
	int N; cin >> N;
	vector<string> V(N);
	for (int i = 0; i < N; i++)
		cin >> V[i];
	string s = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	int x = 0;
	vector<vector<int> > v(N);
	for (int i = 0; i < N; i++)
		for (int j = 0; j < V[i].length(); j++) {
			char c = V[i][j];
			int k;
			for (k = 0; k < 36; k++)
				if (s[k] == c)
					break;
			v[i].push_back(k);
			x = max(x, k + 1);
		}
	ll mini = LLONG_MAX;
	for (int i = 0; i < N; i++) {
		ll y = 0;
		for (int j = 0; j < v[i].size(); j++)
			y = y * x + v[i][j];
		mini = min(mini, y);
	}
	cout << mini << endl;
}