using System;

public class Program

{

    private static string s;

    private static string Convert(int n)

    {

        n = n+64;

        s = ((char)n).ToString();

        return s;

    }

    public static string ConvertToTitle(int n) 

    {

        while(n>26)

        {

            s += Convert(n/26);

            n-=26;

            continue;

        }

            s += Convert(n);

        return s;

    }

    public static string ConvertToT(int n) 

    {

        while(n>0)

        {

            n--;

            s += ((char)(n%26 +'A')).ToString();

            n/=26;

        }

        return s;

    }

    //Last executed input: 1000000001

    //public static int TitleToNumber(string s) {

    //}

    public static void Main()

    {

        Console.WriteLine(ConvertToT(57));

    }

}