using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Enu = System.Linq.Enumerable;
using System.Numerics;

class Program
{
    Dictionary<char, int> Dic = new Dictionary<char, int>();
    void Solve()
    {
        int N = reader.Int();
        var S = reader.StringArray(N);
        int maxLen = S.Max(s => s.Length);
        S = S.Select(s => s.PadLeft(maxLen - s.Length, '0')).ToArray();
        for (int i = 0; i <= 9; i++) Dic[(char)('0' + i)] = i;
        for (int i = 0; i < 26; i++) Dic[(char)('A' + i)] = 10 + i;
        var ans = S.Min(s => Naive(s));
        Console.WriteLine(ans);
    }

    BigInteger Naive(string s)
    {
        BigInteger res = BigInteger.Pow(10, 1000);
        for (int d = 0; d <= 36; d++)
        {
            BigInteger x = 0;
            bool ok = true;
            foreach (char c in s)
            {
                if (Dic[c] >= d) { ok = false; break; }
                x = x * d + Dic[c];
            }
            if (ok && x < res) res = x;
        }
        return res;
    }






    Reader reader = new Reader(Console.In);
    static void Main() { new Program().Solve(); }
}

class Reader
{
    private readonly TextReader reader;
    private readonly char[] separator = { ' ' };
    private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries;
    private string[] A = new string[0];
    private int i;

    public Reader(TextReader r) { reader = r; }
    public Reader(string file) { reader = new StreamReader(file); }
    public bool HasNext() { return Enqueue(); }
    public string String() { return Dequeue(); }
    public int Int() { return int.Parse(Dequeue()); }
    public long Long() { return long.Parse(Dequeue()); }
    public double Double() { return double.Parse(Dequeue()); }
    public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); }
    public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public string Line() { return reader.ReadLine().Trim(); }
    private string[] Split(string s) { return s.Split(separator, removeOp); }
    private bool Enqueue()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return Enqueue();
        A = Split(line);
        i = 0;
        return true;
    }
    private string Dequeue() { Enqueue(); return A[i++]; }
}