using System.Collections.Generic;
using static System.Math;
using System;

public class Hello
{
    public static Dictionary<char, int> d;
    static void Main()
    {
        var s = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        d = new Dictionary<char, int>();
        for (int i = 0; i < 36; i++) d[s[i]] = i;
        var n = int.Parse(Console.ReadLine().Trim());
        var amin = long.MaxValue;
        for (int i = 0; i < n; i++)
        {
            var a = Console.ReadLine().Trim();
            var   maxc =  getMaxc(a);
            amin = Min(amin, calc(a, maxc + 1));
        }
        Console.WriteLine(amin);

    }
    static long calc (string s , int n)
    {
        var s2 = s.ToCharArray();
        Array.Reverse(s2);
        var res = 0L;
        var sL = s.Length;
        var ex = 1L;
        for (int i = 0; i < sL; i++)
        {
            res += ex * d[s2[i]];
            ex *= n;
        }
        return res;
    }
    static int getMaxc(string s)
    {
        var res = 0;
        foreach (var x in s) res = Max(res, d[x]);
        return res;
    }
}