#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp> // for use cpp_int
#include <boost/multiprecision/cpp_dec_float.hpp> // for use cpp_dec_float_100
using namespace std;
using namespace boost::multiprecision;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())
#define endl "\n"
template<class T> void chmax(T &a, const T b){ a = max(a, b); }
template<class T> void chmin(T &a, const T b){ a = min(a, b); }
long long gcd(long long a, long long b) { return (a % b) ? gcd(b, a % b) : b; }
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }

cpp_int stov(string s) {
    string t = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    ll idx = -1;
    rep(i, len(s)) {
        ll cidx = -1;
        rep(j, len(t)) {
            if (s[i] == t[j]) {
                cidx = j;
                break;
            }
        }
        chmax(idx, cidx);
    }
    idx++;
    cpp_int kt = 1, result = 0;
    rrep(i, len(s)) {
        ll cidx = -1;
        rep(j, len(t)) {
            if (s[i] == t[j]) {
                cidx = j;
                break;
            }
        }
        result += kt * cidx;
        kt *= idx;
    }
    return result;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // std::ifstream in("input.txt");
    // std::cin.rdbuf(in.rdbuf());
    ll n;
    cin >> n;
    vector<pair<cpp_int, string>> vp(n);
    rep(i, n) {
        cin >> vp[i].second;
        vp[i].first = stov(vp[i].second);
    }
    sort(all(vp));
    cout << vp[0].first << endl;
    return 0;
}