#include <bits/stdc++.h>
using namespace std;

long long intpow(long long a, long long b) {
    long long ans = 1;
    while (b) {
        if (b & 1)
            ans *= a;
        a *= a;
        b /= 2;
    }
    return ans;
}

int main() {
    int N;
    cin >> N;
    long long ans = intpow(36, 12);

    auto f = [](char c) {
        if (c >= '0' && c <= '9')
            return (int)c - '0';
        else
            return 10 + c - ('A');
    };

    while (N--) {
        string V;
        cin >> V;

        int MAX = 0;
        for (auto& c : V) {
            c = f(c);
            MAX = max(MAX, (int)c);
        }
        MAX++;

        long long res = 0;
        for (auto& c : V) {
            res *= MAX;
            res += c;
        }

        ans = min(ans, res);
    }

    cout << ans << endl;
}