using System.Collections.Generic;
using System.Linq;
using System;

public class Hello
{
    public static void Main()
    {
        var z = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        var d = new Dictionary<char, int>();
        for (int i = 0; i < 36; i++) d[z[i]] = i;
        var ans = new List<long>();
        var n = int.Parse(Console.ReadLine().Trim());
        for (int i = 0; i < n; i++)
        {
            var s = Console.ReadLine().Trim();
            var a = getN(d, s);
            var a2 = getV(d, s, a);
            ans.Add(a2);
        }
        Console.WriteLine(ans.Min());
    }
    public static int getN (Dictionary<char,int> d,  string s)
    {
        var ans = 0;
        for (int i = 0; i < s.Length; i++)
            ans = Math.Max(ans, d[s[i]]);
        return ans + 1;
    }
    public static long getV (Dictionary<char,int> d , string s , int n)
    {
        var sL = s.Length;
        var ans = 0L;
        for (int i = 0; i < sL; i++)
            ans += (long)Math.Pow(n, sL - 1 - i) * d[s[i]];
        return ans;
    }
}