#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define llong long long
#define ullong unsigned long long

int main() {
    int n;
    cin >> n;
    
    string rval = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    map<char, int> rankmap;
    rep(i, rval.length()) rankmap[rval[i]] = i;

    ullong minval = ULLONG_MAX;
    rep(i, n) {
        string s;
        cin >> s;
        int rank = 2;
        rep(j, s.length()) rank = max(rankmap[s[j]] + 1, rank);
        reverse(s.begin(), s.end());
        ullong val = 0;
        ullong rankval = 1;
        for(char c: s) {
            val += rankmap[c] * rankval;
            rankval *= rank;
        }
        minval = min(minval, val);
    }

    cout << minval << endl;
}